Arectangle has a width of 3 inches. the rectangle's length is 5 times it's width. what is the area of the the rectangle

Since the area formula for a rectangle is A=lw, A meaning area, l equal to length, w equal to width, you need to use the formula.
Since the rectangle's length is 5 times the width, you need to use 5w instead of l.
And the width is 3 inches.
3 x 5 equals 15.
The length is 15 inches.
Now, plug in the equation,
A = 15 x 3
The area of the rectangle is 45 inches.

Do you need with the x value for the minimum? its always between the two intercepts for a parabola