Question

5) x - 4y = 28 -4x - y = 7 Solve each system by elimination

Answer 1

Answer:

(0,-7)

Step-by-step explanation:

x-4y=28      multiply by 4

-4x-y=7       multiply by 1

4x-16y=112

-4x-y=7

cross out the x and add the rest

-17y= 119

divide by -17

y= -7

now you substitute the y in one of the equations.

the reformed equations

we will use the second one

-4x-(-7)=7

two negative becomes a plus

-4x+7=7

now you minus the 7 to both sides

-4x=0

now divide by -4

x=0

(0,-7)

Answer 2

Answer:

x = 0, y = -7

Step-by-step explanation:

x - 4y = 28

-4x - y = 7

____________

x - 4y = 28

-16x - 4y = 28

____________  _

17x = 0

x = 0

0 - 4y = 28

y = -7