Topic 5 review of systems Question 18

Question

Solve the system using addition.



7x+8y = -23

-7+y = 68

Question content area bottom

Part 1

The solution is

enter your response here.

​ (Type an ordered​ pair.)

Answer 1

7x +8y = -23

-7x +y= 68

add to get

9y = 45

y = 45/9 = 5

y = 5

-7x = 68 -5 = 63

x = 63/-7 =-9

x =-9, y = 5

UNLESS you really did mean

7x+8y =-23 and

-7 + y = 68

then

y =68+7 = 75

y=75

7x = -23 -8(75) = -623

x=-623/7 = - 89

x=89

and

7x +8y =-23

8y = -23 - 7(89) = -23 - 623 = - 646

y = -646/8 = -80.75

odds are you meant the first solution and problem as it involves addition, and the answer comes out "cleaner"