posted by .

How do I solve the following problems?

My homework was to correct a puiz that I failed, but I do not know how to solve these problems..please help!

Solving systems of equations using elimination:

7.) 10x - 10y = 0
5x - 4y = 8
I got the right answer because this one was multiple choice, but it was because I guessed...I need to know how to work it out.

8.) -8x - 8y = -8
-5x + 16y = 16

9.)I need this one worked out...I guessed the right answer (7, -7)

2x + 3yy = -7
-3x - 2y = -7

10.) -8x + 8y = -16
-3x + 7y = 10

11. 8x + 14y = 128
6x + 2y = 62

#7:
if 10x-10y=0, then 10x=10y, or x=y
plug that into the other equation to get
5x-4x = 8
x=8, so y=8

the others are basically the same. you can substitute, or eliminate.

#8:
-8x - 8y = -8
-5x + 16y = 16

x+y=1, so y = 1-x
-5x + 16(1-x) = 16
-21x = 0
x=0, so y=1

elimination:
#10
-8x + 8y = -16
-3x + 7y = 10

multiply top by 3 and bottom by -8 to get

-24x + 24y = -48
24x - 56y = -80

-32y = -128
y = 4, so x = 6

Try the others and come back if you get stuck. Show us whatcha got, and we can straighten it out if necessary.

If you get an answer, be sure to plug the values back into both original equations to make sure it is right.

## Similar Questions

1. ### Math

I am having problems understanding how to solve problems like the following: a2 + b2 = c2 Please help me where I can understand solving problems such as the one above.
2. ### algebra

I have a few problems I need you to take a look at and tell me if I arrived at the right answer. 1. I am to use the intercepts to graph the equation x+3y=6 I used the formula y=mx+b using 3 and -6 for x I got these as my ordered pairs …
3. ### Algebra 2

Solving systems of linear equations in three variables. Ok so i don't really totally get these problems. Can you help me solve this one?
4. ### algebra

i need help with these problems (either a solution or how to plug them into a graphing calculator): 1) Solve by substitution or elimination 4/x + 1/y + 2/z = 4 2/x + 3/y - 1/z = 1 1/x + 1/y + 1/z = 4 2)Solve the system of equations …
5. ### Algebra

Solve the following systems of equations using the addition (elimination) method. -2x+3y=5 2x-y=1
6. ### Algebra

Solve the following systems of equations using the addition (elimination) method. 5x+y=2 3x+y=1
7. ### Algebra

Solve the following systems of equations using the addition (elimination) method. 5x=20+y 16=3y+4x
8. ### Math

Solve the following system of equations using both substitutio and elimination y=-x+4 y=-2x-4 Do I do what I do with the previous problems
9. ### Algebra SOLVING LINEAR EQUATIONS AND INEQUALITIES

Please help Im am Grade 5 and my teacher is letting me do this. 1. Solve the solution by using elimination and substitution 3/x - 2/y = 14 6/x + 3/y = 7 2. Solve by eliminating x (this is solving 3 linear equations) then substitute …