Question

Please help. I will give a medal and fan.


Solve each system using substitution. Check your solution.

m=5p+8
m=-10p+3

Answer 1

It gives you two equations for the variable m.. So it depends on your preference of either substituting (-10p+3) for m into the first equation or substituting (5p+8) into the second equation.. So which one do you prefer?

Answer 2

im not so sure what that means, given i don't know any of this stuff, but lets go for the second one?

Answer 3

Okay, let's start from the beginning if you don't know how to do it. Are you saying that you don't know how to do substitution?

Answer 4

yeah.

Answer 5

Here is a website that'll help you... http://www.mathsisfun.com/algebra/substitution.html read this first and then come back :)

Answer 6

hmm, i knew that... but I meant like i dont understand how to solve the problem and stuff.

Answer 7

Okay. You have two equations for the variable m. Both equations EQUAL m.

Answer 8

m is equal to both (5p+8) and (-10p+3).

Answer 9

So if m is equal to both those two equations.. Those two equations are equal to each other. It's like saying a = b = c.

Answer 10

So what can you do with those two equations to solve for x?

Answer 11

you can add them together?

Answer 12

If a = b, it wouldn't be the same thing as a + b , right?
For example. 2=2 is not the same as 2+2.

Answer 13

wait... you meant to solve m? not x?^^

Answer 14

Yes, sorry, m. :)

Answer 15

ok, and yeah. thats not the same thing. so what do we do?

Answer 16

If a=b, and b=c.... You could substitute c in for b, so a=c. Do you get that part? :P

Answer 17

but then where would the b go? lol

Answer 18

That's the point of substituting. You're substituting so that you can get rid of the b.

Answer 19

oh, ok :) i get it.

Answer 20

but in this case, there isnt a third letter..

Answer 21

Yes, that was just an algebraic law that I was explaining to you. The name's slipping my mind right now but it's an accepted rule.

Answer 22

Okay, now that you get that part, we can look at the two equations again. m=5x+8, m=-10x+3.

Answer 23

yup

Answer 24

Oops, p, not x.
m=5p+8, m=-10p+3.
If both (5p+8) and (-10p+3) are equal to m, what can you do?
BOTH of them are equal to m.

Answer 25

This is like saying an apple is a fruit, and a fruit is a food. Therefore, an apple is a food.

Answer 26

well, you can make them equal then? since you cant add them?

Answer 27

YES, bingo! You set them equal to each other because they're BOTH equal to m, which makes them equal.

Answer 28

Now, if you set them equal to each other, what would you get for the value of p?

Answer 29

im not sure how to make them equal though haha thats the problem.

Answer 30

(5p+8) is equal to (-10p+3), right?

Answer 31

the = sign basically means "is equal to"

Answer 32

Do you get it now? :)

Answer 33

well, yeah. but how do I make them into 1 equation?....

Answer 34

@dixiemitsy I mean isnt that what I'm supposed to do?

Answer 35

Sorry, my internet got disconnected! And yes... if you set them equal to each other, 5p+8=-10p+3. Now you can just collect like terms. Put the p's on one side and the numbers on the other. You can then solve for p.