The area of the rectangle is 35cm squared if the bottom and top of the rectangle are x+2 and the left and right side equals x, what is the expression of rectangle in terms of x?

1 Answer
Jul 19, 2017

Answer:

#x=5color(white)(.)cm#

Explanation:

Area is width times length.

Let width (shortest) be #w=x#
Let the length be #L=x+2#

Area#->wL=35 cm^2#

Drop the units of measurement for now

#x xx (x+2) = 35#

#x^2+2x=35#

Subtract 35 from both sides

#x^2+2x-35=0#

Notice that #5xx7=35 and 7-5=2#

Factorising

#(x-5)(x+7)=0" " =>" " x=5 and -7#

The -7 is not a logical solution for this question so ignore it

#x=5color(white)(.)cm#
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Check
#w=x=5#
#L=x+2=7#

Area #=5xx7=35# as expected