Write 9x + 3y = 15 in slope-intercept form.

y = 5-3x

Step-by-step explanation:

First, you want to divide both sides of the equation by 3, so we have the equation in the simplest form. Thus, we have an equation: 3x + y = 5.

Slope intercept form means the equation is in the y  = mx + b form. In this case, y is y, m is 3 (coefficient of x) x is x, and b is 5. So, subtracting 3x from both sides means we have our answer of y=5-3x.

A = lw

P = 2l +2w

20 = 2l + 2w.

We express the length using (1).

2l = 20 - 2w

l = 10 - w.

We write the area using the width and length expression using width.

A = w(10 - w).

A = 10w - w2 .

The relationship of the area is quadratic. It has a max value that is where the vertex of the parabola is. The vertex is the average of the two zeros of the equation. We have

w1 = 0

and

w2 = 10.

1/2 (0 + 10) = 5 feet.

Martha will have largest area garden if (l = w = 5 feet).

A = 5x5 = 25 ft2

Note, if l = 4 and w =6,

A = 4x6 =24 ft2.