Area and perimeter

Question

A rectangle has sides expressed as x+9 and 5x-7. Write both the area and perimeter of the rectangle as a simplified polynomial. 

Answer 1

Area:

 

A = (x+9)(5x-7) = 5x^2 -7x + 45x - 63

 

A = 5x^2 + 38x - 63

 

Perimeter:

 

P = 2 [(x+9) + (5x-7)] = 2(6x+2) = 12x + 4