# math

posted by .

Hi, I am taking Algebra 2 and I need help with some Substitution method problems:

x+12y=68
x=8y-12

x+3y=7
2x-4y=24

3a+b=3
2a-5b=-15

-6=3x-6y
4x=4+5y

• math -

I'll do one for you. They all work the same way. You need the practice doing them yourself.

Substitute 8y - 12 for x in the first equation.
8y - 12 + 12y = 68
20 y = 80
y = 4
x = 8y - 12 = 32 - 12 = 20

## Similar Questions

1. ### Algebra

Can someone show me step by step how to do this problem to have an example to go by so I will be able to do my other problems. Thanks Solve by substitution 4x-12y=5 -x+3y=-1 I know that you have solve one of the equations. I have picked …
2. ### Math

How do I solve these problems, I really need help. Solve by substitution method 6x+5y=17 x=53-8y Solve by elimination method 2x+3y=5 4x+6y=10
3. ### Algebra

Hi. I am having some problems with substitution method and i just can't seem to get these right. I have 1. 2x - 3y = -1 with y = x-1 2. -4x + y = 6 with -5x- y = 21 and finally, 3. -5x + y =-3 with 3x -8y = 24
4. ### Algebra

Hi. I am having some problems with substitution method and i just can't seem to get these right. I have 1. 2x - 3y = -1 with y = x-1 2. -4x + y = 6 with -5x- y = 21 and finally, 3. -5x + y =-3 with 3x -8y = 24
5. ### Algebra II

Solve the given system by using a substitution method 9x-2y=3 3x-6=y If you could show the steps because I have 10 problems for homework and I just need an example Thanks
6. ### algebra

use the Substitution Method. Please give it a try. y = 3x + 4 5x + 3y = 12 Why is the substitution method preferred in this case?
7. ### Pre-algebra

I have some practice problems, and I need to have them worked out, showing your work. I will gain a better understanding of these problems by practicing them. Thank you. (6x+1)(x^2-9x+5) (2x^4+3)(4x^3+2) (12y^3+8y^2+20y)divided 2y …
8. ### Pre-algebra

I have some practice problems, and I need to have them worked out, showing your work. I will gain a better understanding of these problems by practicing them. Thank you. (6x+1)(x^2-9x+5) (2x^4+3)(4x^3+2) (12y^3+8y^2+20y)divided 2y …
9. ### Algebra 1

bobpursey, In this problem you helped me with earlier: Solve using any appropriate method. y = 2× - 5, y = ½× + 1 Substitution, substitute for y. 2×-5=½ × + 1 3/2 x=6 x=4 y= 2*4-5=3 How did you choose which method you were going …