Question

-7x - 8y = 9 4x -9y = 22

Answer 1

Answer:

x=1 and y=−2

Step-by-step explanation:

Multiply the first equation by 9,and multiply the second equation by -8.

9(−7x−8y=9)

−8(4x−9y=22)

Becomes:

−63x−72y=81

−32x+72y=−176

Add these equations to eliminate y:

−95x=−95

Then solve−95x=−95for x:

−95x

−95

=

−95

−95

(Divide both sides by -95)

x=1

Now that we've found x let's plug it back in to solve for y.

Write down an original equation:

−7x−8y=9

Substitute1forxin−7x−8y=9:

(−7)(1)−8y=9

−8y−7=9(Simplify both sides of the equation)

−8y−7+7=9+7(Add 7 to both sides)

−8y=16

−8y

−8

=

16

−8

(Divide both sides by -8)

y=−2