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We have a rectangle of dimensions x - 2 by 2x + 5 such that its area is 8x-6 . What is the value of x?

 Apr 16, 2022
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Area of rectangle  =   product of the dimensions

 

(x - 2) (2x + 5)   =  8x  - 6      simplify

 

2x^2  - 4x + 5x   -10   = 8x   -  6        rearrange as

 

2x^2 + x -10  = 8x -  6

 

2x^2 - 7x - 4   =  0           factor  as

 

(2x + 1)  ( x - 4)   =   0

 

We need a positive value for x   .....the second factor  set to  0   will give us that

 

x  - 4 =   0

 

x =  4

 

cool cool cool

 Apr 17, 2022

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