Question

@jim_thompson5910

If (x-2)^2=25 and x<0, what is the value of x?

-23
-7
-5
-3
-2

Answer 1

take the square root of both sides
don't forget the \(\pm\)

Answer 2

I squared both sides and solved for x but it wasn't there.

I just hate the SAT math lol

Answer 3

You need to isolate x. So your first step is to undo that squaring exponent.

Answer 4

Ohhh right so it would be -3.

Answer 5

square root, not square

Answer 6

you don't square both sides

you need to undo squaring (so square root)

Answer 7

yes

Answer 8

checking your answer is always a good idea


Check:

(x-2)^2=25

(-3-2)^2=25 ... replace every x with -3

(-5)^2 = 25

25 = 25 ... checks out

Answer 9

I know I meant square root it.

See I just used +5 then added 2 to get 7 and just chose -7 because idk instead of using -5+2=-3

Answer 10

I dont work well when I'm being timed. Okay next one

Answer 11

Let's check x = -7

(x-2)^2=25

(-7-2)^2=25

(-9)^2 = 25

81 = 25 ... this is a false equation, so x = -7 is not the answer

Answer 12

even though you are in a timed setting, checking helps

Answer 13

but I can see how you got it since x = 7 works

(x-2)^2=25

(7-2)^2=25

(5)^2=25

25 = 25

Answer 14

If m=t^3 for any positive integer t, and if w=m^2+m, what is w in terms of t?

t^2+t
t^3
t^3+t
t^5+t^3
t^6+t^3

Answer 15

w=m^2+m is in terms of m

we want the right side to be just t

thankfully m is in terms of t since m = t^3

Answer 16

so wherever you see an 'm' you replace it with t^3

and simplify

Answer 17

Oh duh. Wow.

Answer 18

that's ok

Answer 19

t^6+t^3

I always misread and freak about about questions like that even though they are easy

Answer 20

just take your time and follow the set up gameplan

Answer 21

Its just they dont give us a lot of time lol

Answer 22

it's better to execute properly than go too fast

Answer 23

that's true, which is why you practice

Answer 24

if the problem seems too tough, then skip it and move onto other ones

get those out of the way and you'll build up momentum to come back and finish the ones you skipped

Answer 25

just make sure you don't go too fast or take too long on one problem

Answer 26

Okay next one: (this one has xtriangle so delta x? So I'll use xt because I cant put a triangle)

For all positive integers x, let xt be defined to be (x-1)(x+1). Which of the following is equal to 6t-5t

I just put t there because there is no x just a triangle and the answer choices only have triangles and no x's..

2t+1t
3t+2t
4t+3t
5t+4t
6t+5t

Answer 27

hmm odd notation

so you have \(\Large x\Delta\) or \(\large \Delta x\) ?

Answer 28

Its x with a colored triangle after it.

But that's only when it says let let xtriangle be defined etc etc.

But in the 6-5 and all the answer choices there are just colored in triangles after each number

Answer 29

I'll post a picture

Answer 30

thanks

Answer 31

Its confusing to me too lol

Answer 32

the SAT is always confusing lol

Answer 33

I know so dumb

Answer 34

they're the masters at making things more complicated than they have to be

Answer 35

Exactly. -_-

Answer 36

thanks

Answer 37

No thank you lol

Answer 38

yep, I remember this cryptic bs...lol

anyways, let's make the triangles 't's like you have it

Answer 39

since xt = (x-1)(x+1) this means

6t = (6-1)*(6+1) ... replaced every x with 6 (xt ---> 6t)

6t = 5*7

6t = 35

Answer 40

and

5t = (5-1)*(5+1)

5t = 4*6

5t = 24

Answer 41

So...

6t - 5t = 35 - 24 = 11

Answer 42

pic just loaded i remember doing this question from the collegeboard book

Answer 43

The final result of 6t - 5t is 11

so we have to find the answer choice that also gives you a result of 11

Answer 44

Ohhh okay so 6 and 5?

Answer 45

6t+5t?

Answer 46

you mean choice E?

Answer 47

let's find out

6t = 35 (work shown above)

5t = 24 (work shown above)

which means

6t + 5t = 35+24 = 59

that's not equal to 11 like we want, so choice E is eliminated

Answer 48

Oh.. I was thinking (6-1)(5+6) oh I added them ugh oops

Answer 49

always stick to the definition xt = (x-1)*(x+1)

Answer 50

This problem is really confusing me I'm sorry... so how do I find the answer?

Answer 51

Let's check choice A

Answer 52

well we're looking for which answer gives us 11
ill try choice b

Answer 53

Oh wait I know how to find the answer now one second

Answer 54

xt = (x-1)(x+1)
2t = (2-1)(2+1)
2t = 1*3
2t = 3

---------------

xt = (x-1)(x+1)
1t = (1-1)(1+1)
1t = 0*2
1t = 0

---------------

so,

2t + 1t = 3 + 0 = 3

that means choice A is out

Answer 55

the good thing about multiple choice is that you can check each possible choice with the answer you want

in this case, we want 11 to be the result

so far, we haven't found it

Answer 56

It's b

Answer 57

good

Answer 58

you'll find that 3t = 8 and 2t = 3

so 3t + 2t = 8+3 = 11

Answer 59

it's a good idea to check the others, but I have a feeling they are wrong

Answer 60

Thanks sorry I'm kind of in a hurry it's getting late, but I understand that one now.

If x^2/y is an integer, but x/y is not an integer, which of the following could be the values of x and y?

x=1 y=1
x=3 y=2
x=4 y=2
x=6 y=4
x=9 y=3

Answer 61

I did check the others when I tried the others to get the answer lol

Answer 62

again we have a list of choices, so why not check them all

Answer 63

this is really just where you plug in the answers and see which answers fits what is asked

Answer 64

checking A

x^2/y = (1^2)/1 = 1/1 = 1 ---> integer

x/y = 1/1 = 1 ---> integer

so A is out

Answer 65

A is out because we want x/y to NOT be an integer

Answer 66

So that means
E and C are out too

Answer 67

good

Answer 68

nice job on eliminating answers

Answer 69

But B and D are both not integers.

And I did all this while taking the test and got stuck there.

Answer 70

checking B x=3 y=2

x^2/y = (3^2)/2 = 9/2 = 4.5 ---> not an integer

so B is out because x^2/y has to be an integer

Answer 71

Ohhh right I see

Answer 72

checking D x=6 y=4

x^2/y = (6^2)/4 = 36/4 = 9

x/y = 6/4 = 3/2 = 1.5

so that means D is the answer

Answer 73

x^2/y is an integer, while x/y is not

Answer 74

not an integer

anyways if you really get stuck just plug in each answer choice