Question

I have no clue what i'm doing here...
If you were to use the elimination method to solve the following system, choose the new system of equations that would result after the variable z is eliminated in the first and second equations, then the second and third equations.

3x – 5y + 2z = 7
4x + 9y – z = 2
x – 3y + 3z = 7

11x + 13y = 11
13x + 24y = 13

11x + 13y = 11
3x – 5y = 7

x – 3y = 7
13x + 24y = 13

x – 3y = 7
3x – 5y = 7

Answer 1

after the variable z is eliminated in the first and second equations

that means look at the 1st two equations. Look at the z's +2z in the 1st and -z in the 2nd
you are supposed to say " if I multiply -z times 2 to get -2z I can add it to the +2z to get 0"
that means: multiply the 2nd equation by 2 (all the terms, both sides of the =) and then
add the result to the 1st equation.

Answer 2

then the second and third equations.
now look at the z's in the 2nd: -z and the third eq: +3z
the idea is multiply the 2nd equation by 3 (this will make -z be -3z) and add the result to the 3rd equation

Answer 3

Thank you! c:

Answer 4

choice A looks good