A rectangle's width is x and its length is 2x-1. Its area is 21. Find its dimensions.
my work so far:
21 = x(2x +1)
21 = 2x^2 + x
I was wondering how I would continue to solces this problem.
next steps:
2x^2+x-21 = 0
(2x+7)(x-3) = 0
x = -7/2 or 3
since real-world figures do not have negative dimensions, the rectangle is thus 3x7.
Which you probably already guessed, since the only factors of 21 are 3 and 7!