The area of the rectangle is 36cm^2. What are the dimensions. Width: x-5, length: x?

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Answer 1 · 2018-06-05T17:23:57

#color(blue)("Length"=9cm)#

#color(blue)("Width"=4cm)#

Area of a rectangle is:

#"Area"="length"xx"width"#

we are given the area.

#"area"=36cm^2#

and the length and width:

#"length"=x#

#"width"=x-5#

So:

#x(x-5)=36#

Expanding bracket:

#x^2-5x=36#

#x^2-5x-36=0#

Factor:

#(x+4)(x-9)=0=>x=-4 and x=9#

We can't have negative length, so:

#x=9#

#"Length"=9cm#

#"Width"=9-5=4cm#