Question

The width of a rectangle is 5 cm less than half its length. Its area is 72cm squared. Find the length and the width of the rectangle

Answer 1

W=1/2L-5
A=LW=72

Answer 2

use these two equations

Answer 3

but how do i do it?

Answer 4

plug W=1/2L-5 into
LW=72 and solve for L first

Answer 5

ok i got the answer can you tell me so i can check to make sure it is correct?

Answer 6

just plug 1/2L-5 where you see W in
LW=72
like this
L(1/2L-5)=72
now disbribute
1/2L^2-5L=72
subtract 72 on both sides
1/2L^2-5L-72=0

now go ahead in get rid of that nasty coefficient on L^2 by multiplying both sides by 2
L^2-10L-144=0
(L-18)(L+8)=0
L=18 or L=-8
negative length is crazy talk so
we have L=18
now you can plug this value into W=1/2L-5 to find W