Eleanor and Max used two rectangular pieces of plywood, placed end-to-end, to make a long rectangular stage for the school play. One board was 7 feet long, and the other was 7 1/2 feet long. The two pieces of plywood had equal widths. The total area of the stage
was 97 7/8 square feet. What was the width of the plywood?

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Step-by-step explanation:

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

x-3y=4

step-by-step e