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.

(3a)(2ab) - (7a²)(2b)
(3 x 2)(a x a x b) - (7 x 2)(a² x b)
(6)(a¹⁺¹ x b) - (14)(a²b)
6a²b - 14a²b
-8a²b

To find the diagonal we need to know the length of one of the square's sides. We know the area and the area of a square is the length of one side squared:

a = s²

so the length of one side of the square is:

s = \( \sqrt{a} \) = \( \sqrt{64} \) = 8

The Pythagorean theorem defines the square of the hypotenuse (diagonal) of a triangle with a right angle as the sum of the squares of the other two sides:

c² = a² + b²
c² = 8² + 8²
c² = 128
c = \( \sqrt{128} \) = \( \sqrt{64 x 2} \) = \( \sqrt{64} \) \( \sqrt{2} \)
c = 8\( \sqrt{2} \)

The formula for area is πr²:

a = πr²
a = π(2²)
a = 4π

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 1 + 1 + 3 + 5
p = 10

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the < sign and the answer on the other.

-8b + 3 < 5 - 7b
-8b < 5 - 7b - 3
-8b + 7b < 5 - 3
-b < 2
b < \( \frac{2}{-1} \)
b < -2