To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

(9a)(4ab) - (5a²)(4b)
(9 x 4)(a x a x b) - (5 x 4)(a² x b)
(36)(a¹⁺¹ x b) - (20)(a²b)
36a²b - 20a²b
16a²b

The formula for area is πr². Radius is circle \( \frac{diameter}{2} \):

r = \( \frac{d}{2} \)
r = \( \frac{8}{2} \)
r = 4
a = πr²
a = π(4²)
a = 16π

You need to find the value of c so solve the first equation in terms of y:

-9c + y = -7
y = -7 + 9c

then substitute the result (-7 - -9c) into the second equation:

-8c - 4(-7 + 9c) = 3
-8c + (-4 x -7) + (-4 x 9c) = 3
-8c + 28 - 36c = 3
-8c - 36c = 3 - 28
-44c = -25
c = \( \frac{-25}{-44} \)
c = \(\frac{25}{44}\)

The slope of this line is the change in y divided by the change in x. The endpoints of this line segment are at (-2, 3) and (2, -3) so the slope becomes:

A right angle measures 90 degrees and is the intersection of two perpendicular lines. In diagrams, a right angle is indicated by a small box completing a square with the perpendicular lines.