Question

PLEASE HELP! /:

Evaluate the following expression using the values given:

Find 2r^2 + 3s^3 - r^2 + 4t^2 - r^2 if r = -2, s = -3, and t = 5.

a) -19
b) -37
c) 27
d) 19

Answer 1

I came out with the answer 127 and there isn't any other answers.. I'm so confused. I suck at math, so I wouldn't be surprised if I did the problem wrong.

Answer 2

Plug in those values into r, s and t

\(\ \color{greenyellow}{R = -2} \)
\(\ \color{#19FF00}{S = -3} \)
\(\ \color{aqua}{ T = 5} \)

\(\ 2\color{yellowgreen}{r}\)^2 + \(\ 3\color{#19FF00}{s}^3 \) - \(\ \color{yellowgreen}{r}^2 \)^2 + 4\(\ \color{aqua}{t}^2\) - \(\ \color{yellowgreen}{r}^2\)

Answer 3

uuummm.... explain ^^^^

Answer 4

@tHe_FiZiCx99 this is what I did...

2(-2)^2+3(-3)^2-(-2)^2+4(5)^2-(-2)^2
2(4)+3(9)-4+4(25)-4
8+27-4+100-4
127

Answer 5

its suppoed so be 3s^3 not squared

Answer 6

so r = -2 , s = -3 , t = 5
2*(-2)^2 + 3*(-3)^3 - (-2)^2 + 4*(5)^2 - (-2)^2
= 8 - 81 - 4 + 100 - 4
= 108 - 89
= 19

Answer 7

a more simpler way would be to simplify the original equation first
\[2r^2 + 3s^3 - r^2 + 4t^2 - r^2\]
\[2r^2 + 3s^3 - 2r^2 + 4t^2\]
\[3s^3 + 4t^2\]
and plug in s and 3 to get your answer

Answer 8

t sorry

Answer 9

hey @jayz657 why does your answer always show [Math Processing Error]?

Answer 10

Switch browsers

Answer 11

it looks fine for me

Answer 12

@DragonSage Sorry for my dumbness, but on the question, shouldn't it be ''2*(-2)^2''... I thought ^2 meant to for instance if the question were 2^2, the answer would be 4. If that's the case in this, shouldn't the answer be 16? Because 2*(-2) = 4. And 4 times 4 is 16. Sorry if this is confusing. I'm really just trying to understand. ):

Answer 13

@kmullis6 look at what i wrote and plug in the values for s and t

Answer 14

@jayz657 Did that make any sense tho or am I just stupid? lol :P

Answer 15

no your right but the mistake you made earlier wasnt there it was at
3s^3 you wrote 3s^2 instead of 3s^3

Answer 16

oh ok @jayz657

Answer 17

So just to verify, the first answer would be 8 or 16? Still confused on what to do there... @jayz657

Answer 18

\[\huge 2r^2 =2(r^2) = 2*(-2)^2=2*4 =8\]

Answer 19

That's why I'm confused, because I was always taught for instance, if the problem was 5^2, the answer would be 10. Like 5 times 5. Do the rules of ''^'' change here? I feel so stupid? :P

Answer 20

I don't really get what you mean. if you mean something like:\[\huge 2*5^2 = 2*(5*5)= 2*25=50\]

Answer 21

I was taught in school that you didn't multiply like that when it came to things like 5^3, for instance. If you forgot and did 5 times 3 and put 15 down you were wrong. It was supposed to be worked out like 5 times 5 times 5 = 125. Sorry that it's confusing. It's just what I was taught. @bibby

Answer 22

That's what I was doing. Everything I did followed PEDMAS/PEMDAS.

All I was doing was evaluating the exponent part first. So (-2)^2 = 4 and then I multiplied that by 2

Answer 23

BEDMAS, sounds so much better even though it's parentheses not brackets.

Answer 24

Then, I guess I really don't know what I was doing lol... I was doing 2*(-2)^2 and getting 16 because 2*(-2) = 4. 4^2 = 16.

Answer 25

Ooh. That's why I separated the terms in parentheses. You can't do that.

\[\large 2{(-2)}^2\] is the same thing as
\[\large 2*[{(-2)}^2]\]

Answer 26

Result is 19 btw

Answer 27

Because I'm batman.

Answer 28

Yeah sorry, my walmart internet wouldn't reconnect ._.

Answer 29

I get confused with Algebra easily. I'm only on my 2nd assignment in Algebra 1, so I'm sorry for spending all this time on this lol. But what happens to the 2? @bibby

@iambatman Lol :P

@tHe_FiZiCx99 It's ok (:

Answer 30

lol I'll rewrite all the work, gimme a sec

Answer 31

Sowwie :<

Go bibbeh!!

Answer 32

hahaha i saw that @bibby :P

Answer 33

the mods are also gonna see that :'(

Answer 34

I missed it, share :3

Answer 35

awhhh.. i'm sorry ):

Answer 36

Missed it D;

Answer 37

Find 2r^2 + 3s^3 - r^2 + 4t^2 - r^2
r = -2, s = -3, and t = 5.
\[\huge 2r^2 + 3s^3 - r^2 + 4t^2 - r^2\]\[\huge 2[r^2] + 3[s^3] - r^2 + 4[t^2] - r^2\]
\[\huge 2[(-2)^2] + 3[(-3)^3] - (-2)^2 + 4[5^2] - (-2)^2\]
I was just being mean to fiz

Answer 38

Right on

Answer 39

haha

Answer 40

\[\large 2[(-2)^2] + 3[(-3)^3] - (-2)^2 + 4[5^2] - (-2)^2\]

Answer 41

Fahk ;-; missed it D:

Answer 42

\[\large 2[4] + 3[-27] - [(-2)^2] + 4[25] - [4]\]

Answer 43

All of those parenthesis confuse me. Aahhh! -____-

Answer 44

those brackets are just like parentheses. They mean, "I need a value before you can do any math with me"

Answer 45

They're just put there to not mixed them up, think of them as instead a + b+ c = (a) + (b) + (c)

Answer 46

What's the difference between [ ] and ( )?

Answer 47

Nothing, they're all the same, too many will look confusing

Answer 48

Oh. Makes sense. @bibby @tHe_FiZiCx99

Answer 49

It's just to differentiate from what's going on

Answer 50

Yeah ^

Answer 51

@iambatman ok thanks (:

Answer 52

cause something like \[\large 3(−3)^3−(−2)2\]
gets confusing

Answer 53

But when dealing with domain and range, then that's totally different :P

Answer 54

anyhow\[\large 2[4] + 3[-27] - [(-2)^2] + 4[25] - [4]\]\[\large 8 + -81 - 4 + 100 - 4\]

Answer 55

Go bibbbbby!!!!!

Answer 56

And that's 19!

Answer 57

Batman is always right

Answer 58

good work team

Answer 59

said no one ever.

Answer 60

Awh bib ;)

Answer 61

my only regret is the medals aren't distributed evenly

Answer 62

♥

Answer 63

♥♥

Answer 64

Aw yeah that sucks ): @bibby

Answer 65

♥♥♥

Answer 66

well... that escalated quickly..

Answer 67

hahaha just a little lol :P @DragonSage

Answer 68

It actually escalated pretty reasonably. 1 heart per post

Answer 69

anyhow I'll stop spamming. Apologies if my brackets made things seem unclear. They're just a way of making things more legible.

Answer 70

No it made sense after explained. Thank you so much for helping me understand this stuff better. (: @bibby

Answer 71

And thank y'all too! @tHe_FiZiCx99 @iambatman @DragonSage

Answer 72

Do you mind helping me on one more? I think I know the answer. Just wanna make sure.
@bibby

Answer 73

Evaluate the following expression using the given values:

Find x - 3y if x = 3 and y = -2.

-9

-3

3

9

I think the answer is 9.

Answer 74

3-3(-2) = 3+6 = 9

Answer 75

In general, it's one problem to a question but meh
\[\large x-3y\]\[\large 3-[3*(-2)]\]\[\large 3-[-6]\]9

Answer 76

thx bby

Answer 77

Yay! Thanks guys! @iambatman @bibby

Answer 78

Bibby's a boss

Answer 79

@iambatman Can I get your help again? sorry for bothering you /:

Answer 80

You can post new questions and tag us all

Answer 81

Ok. I feek kinda bad tho cause yall spent forever on just that one question lol @bibby

Answer 82

Make it up to us by posting another question where we can get more medals :D

Answer 83

Simplify the following expression:

2x - 2y + 5z - 2x - y + 3z

x - 3y + 8z

2x - 2y + 8z

3y + 8z

-3y + 8z

So, I worked this problem out, and at the end, I got 4x - 3y - 8z. The answer was for sure C because I looked it up. What I'm wondering, is what happened to the 4x? @bibby @tHe_FiZiCx99

Answer 84

I'll try color coding this

Answer 85

2x - 2x - 2y - y + 5z + 2z
-3y + 8z

Answer 86

That's what I did, because it's in my lesson. I arranged them exactly like that. What happened to the 4x tho? /:

Answer 87

2x-2x = 0

Answer 88

To get 4x - 3y - 8z
The equation would be 2x - 2y + 5z + 2x - y + 3z

Answer 89

OH MY GAAASHHH! I WROTE IT DOWN WRONG AGAIN! I'M SO ANGRY WITH MYSELF! Sorry guys. ):

Answer 90

Stop apologizing :)
This happens. Everyone makes careless mistakes here and there. That's why you're doing homework. So that you don't flub up the test.

Answer 91

yeah what he said ^^^

Answer 92

Haha I know, but I feel like an idiot. Math's my worst subject, and this is usually why I don't do so well in this subject.

Answer 93

If it makes you feel better, I'm also an idiot and slept throughout most of my high school classes and still passed

Answer 94

^ me too