width of a rectangle is 7 cm less than twice the length the area is 30 cm2 find the dimensions

Question

the widthof a rectangle is 7cm less than twice its length its area is 30 cm squared find the dimensions of the rectangle

Answer 1

Let L=length, so width=2L-7. Area=30=L(2L-7)=2L^2-7L, which can be written: 2L^2-7L-30=0=(L-6)(2L+5), so L=6cm, because L can't be negative. Width=2L-7=5cm. Area=5*6=30 which is correct.