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.

(4a)(7ab) + (9a²)(8b)
(4 x 7)(a x a x b) + (9 x 8)(a² x b)
(28)(a¹⁺¹ x b) + (72)(a²b)
28a²b + 72a²b
100a²b

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 equal sign and the answer on the other.

2y - 9 = -3 - 7y
2y = -3 - 7y + 9
2y + 7y = -3 + 9
9y = 6
y = \( \frac{6}{9} \)
y = \(\frac{2}{3}\)

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.

7y - 1 > 1 + 2y
7y > 1 + 2y + 1
7y - 2y > 1 + 1
5y > 2
y > \( \frac{2}{5} \)
y > \(\frac{2}{5}\)

The area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:

a = ½(b + d)(h)
a = ½(7 + 5)(4)
a = ½(12)(4)
a = ½(48) = \( \frac{48}{2} \)
a = 24

The surface area of a cylinder is 2πr² + 2πrh:

sa = 2πr² + 2πrh
sa = 2π(1²) + 2π(1 x 7)
sa = 2π(1) + 2π(7)
sa = (2 x 1)π + (2 x 7)π
sa = 2π + 14π
sa = 16π