The width, w, of a rectangular playground is x+3. the area of the playground is x^3-7x+6. what is an expression for the length of the playground?

We know that the area of a rectangle:

A = l * w

Therefore, x³-7x+6 = length * (x+3) 

If we want to find the length, we must get this alone on the right side of the equation.  We can do this by dividing both sides by the width, which we know is x+3.

Thus, an expression for the length is equal to x³-7x-6/(x+3).

You must first calculate how much the tree needs to grow.
Then you divide that amount by how much the tree grows per year.

37 - 21 1/4 = 36 4/4 - 21 1/4 = 15 3/4

The tree has to grow 15 3/4 ft.

Now you divide 15 3/4 by 1 3/4.

(15 3/4)/(1 3/4) = (63/4) / ( 7/4) = 63/4 * 4/7 = (63 * 4)/(4 * 7) = 63/7 = 9

It will take 9 years.