SOLUTION: The length of a rectangle is (x+4)cm. The width is (x-3)cm. The area of the rectangle is 78cm^2. (a) Use this information to write down an equation in terms of x. (b) Write d

Question 810810: The length of a rectangle is (x+4)cm.
The width is (x-3)cm.
The area of the rectangle is 78cm^2.
(a) Use this information to write down an equation in terms of x.
(b) Write down the length and the width of the rectangle.
I haven't been taught this yet at school but it came up in one of my practice papers :)

Answer by oscargut(2103) (Show Source): You can put this solution on YOUR website!
a) (x+4)(x-3)=78
b)
solving: (x+4)(x-3)=78
x^2+x-12 = 78
x^2+x -90= 0
(x-9)(x+10) = 0
x = 9 or x = -10
since x must be > 0
x = 9
Length = x+4 = 13
width = x-3 = 6
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