Question

The dimensional of a rectangular garden were 4 m by 5 m. Each dimension was increased by the same amount. The garden then had an area of 56 m squared. Find the dimensions of the new garden. ( hint let x be the amount of increase )

Answer 1

w=4+x

l=5+x

A =l*w

substitute

56=(4+x)*(5+x)

foil

56 = 20 + 4x+5x+x^2

56 = x^2 +9x+20

subtract 56 from each side

0 = x^2 +9x -36

factor

0 = (x+12) (x-3)

x+12=0  x-3=0

x= -12 x=3

x cannot be negative  so x=3

new dimensions

w =4+3 =7

l=5+3 =8

Answer: 7m by 8m