Question

Solve the system by substitution.
-x-y-z=-8
-4x+4y+5z=7
2x+2z=4
Please show step by step instructions.

Answer 1

@Tessa___98 Are these 3 different equations or all together?

Answer 2

3 different equations

Answer 3

@Tessa___98 ok lets start with number one

Answer 4

ook

Answer 5

so what's first??

Answer 6

@Tessa___98 1.
solve for x
-x -y -z = -8
add y to both sides
-x -y -z + y = -8 + y
-x -z = y - 8
add z to both sides
-x -z + z = y - 8 + z
-x = y + z - 8
divide both sides by -1
-x/-1 = y + z -8/1

answer -> x = -y - z + 8

Answer 7

Then what @cutelilcigarette??

Answer 8

@Tessa___98 2.
solving for x
- 4x + 4y + 5z = 7
add -4y to both sides
-4x + 4y + 5z + -4y = 7 + -4y
-4x + 5z = -4y + 7
add -5z to both sides
-4x + 5z + -5z = -4y + 7 + -5z
-4x = -4y - 5z + 7
divide both sides by -4
-4x/4 = -4y - 5z + 7/-4

answer -> x = y + 5/4z + -7/4

Answer 9

Thanks a bunch for helping me!!

Answer 10

@Tessa___98 3.
solving for x again
2x + 2z = 4
add -2z to both sides
2x + 2z + -2z = 4 + -2z
2x = -2z + 4
divide both sides by 2
2x/2 = -2z + 4/2
x = - z + 2 <- answer

Answer 11

and your welcome!

Answer 12

Ook so is that all that needs to be done?? @cutelilcigarette

Answer 13

yep!

Answer 14

Ook thanks so so much again for helping!!

Answer 15

welcome <3