For parallel lines with a transversal, the following relationships apply:

• angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°)
• alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°)
• all acute angles (a° = c° = w° = z°) and all obtuse angles (b° = d° = x° = y°) equal each other
• same-side interior angles are supplementary and add up to 180° (e.g. a° + d° = 180°, d° + c° = 180°)

Applying these relationships starting with a° = 38, the value of x° is 142.

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)(2ab) - (7a²)(6b)
(9 x 2)(a x a x b) - (7 x 6)(a² x b)
(18)(a¹⁺¹ x b) - (42)(a²b)
18a²b - 42a²b
-24a²b

The formula for area is πr²:

a = πr²
a = π(4²)
a = 16π

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.

-2z - 6 = \( \frac{z}{8} \)
8 x (-2z - 6) = z
(8 x -2z) + (8 x -6) = z
-16z - 48 = z
-16z - 48 - z = 0
-16z - z = 48
-17z = 48
z = \( \frac{48}{-17} \)
z = -2\(\frac{14}{17}\)

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.

9x - 2 = 9 + 7x
9x = 9 + 7x + 2
9x - 7x = 9 + 2
2x = 11
x = \( \frac{11}{2} \)
x = 5\(\frac{1}{2}\)