Question

The length of a rectangle is 2 feet less than three times the width. If the area of the rectangle is 40 square feet, find the dimensions.

Answer 1

A=L*W
A-Area
L-Length
W-Width

Answer 2

L+2=3W

Answer 3

Doesn't the 40 have something to do with the equation?

Answer 4

A=(3W-2)*W=40
3W^2-2W=40

Answer 5

3W^2-2W-40=0
w=4

Answer 6

so L=10

Answer 7

Can you elaborate more on how you got w

Answer 8

\[ax ^{2}+bx+c=0\]

Answer 9

\[x=\frac{ -b \pm \sqrt{b ^{2}-4ac} }{ 2a }\]

Answer 10

substitute to the formula, here we have W instead of x

Answer 11

Is the first one you showed completing the square?

Answer 12

nope, it's the condition for the second one formula

Answer 13

whenever you have an equation of such kind, you will apply that formula to find x

Answer 14

Oh okay got it. Your just putting it in descending order to do the quadratic formula

Answer 15

i disregarded negative value for width, as width can not be negative

Answer 16

Okay thanks