A rectangular porch has dimensions of (x+3) fet and (x+4) feet. The area of the porch is 132 square feet. What are the length and width of the porch?

Question

can you show me the steps? do I use the quadratic formula?

Answer 1

A=lw

132=(x+3)(x+4)

132=x^2+3x+4x+12

132=x^2+7x+12

x^2+7x+12-132=0

x^2+7x-120=0

factor

120=2*2*2*3*5=(8)*(15) and 15-8=7

(x+15)(x-8)=0

x-8=0

x=8

x+3=11 feet

x+4=12 feet

you can also use the quadratic formula if you like

Answer 2

(x + 3)(x + 4) = 132                    FOIL

x² + 7x + 12 = 132                      subtract 132 from both sides

x² + 7x - 120 = 0                         FOIL

(x + 15)(x - 8) = 0                       zero product rule

 

{-15, 8}                                      -15 is meaningless measure

 

The dimensions are 11 x 12