Question

If you were to use the substitution method to solve the following system, choose the new system of equations that would result if x was isolated in the third equation.

2x – 3y + z = –4
2x – 2y + z = –1
x – 2y + 3z = –6
Answer

–y – 1 = –4
–5x + 4y = –3

y – 5z = 8
2y – 5z = 11

5x + 7y = 6
y – 4 = –1

–7y + 7z = 8
–6y + 7z = 11

Answer 1

Solve for z for either first or second equation and substitute that for either equation [Yes, a lot of either!]

z = -2x + 3y - 4

Second equation: 2x – 2y + (-2x + 3y - 4) = –1
2x - 2y - 2x + 3y - 4 = -1
y - 4 = -1
y = 3

We can apply substitution method to find the x value! Substitute z = -2x + 3y - 4 and y = 3 for the third equation, and we have...

x – 2(3) + 3(-2x + 3(3) - 4) = –6
x - 6 + 3(-2x + 9 - 4) = -6
x - 6 + 3(-2x + 5) = -6
x - 6 - 6x + 15 = -6
-5x + 9 = -6
-5x = -15
x = 3

Finally, substitute x = 3 and y = 3 for either equation and solve for z!

2(3) – 2(3) + z = –1
6 - 6 + z = -1
z = -1

Hence, the solution is (3,3,1) in terms of (x,y,z)

Answer 2

which 1 is it a b c or d??

Answer 3

WAIIT

Answer 4

c

Answer 5

thank youu

Answer 6

It is the second 1. The directions are specific. Solve the third equation for x and substitute. If you do that you will get y-5z=8 and B is the only choice that contains that answer.

Answer 7

ok