Angles around a line add up to 180°. Angles around a point add up to 360°. When two lines intersect, adjacent angles are supplementary (they add up to 180°) and angles across from either other are vertical (they're equal).

You need to find the value of b so solve the first equation in terms of z:

-9b + z = 5
z = 5 + 9b

then substitute the result (5 - -9b) into the second equation:

2b + 1(5 + 9b) = 9
2b + (1 x 5) + (1 x 9b) = 9
2b + 5 + 9b = 9
2b + 9b = 9 - 5
11b = 4
b = \( \frac{4}{11} \)
b = \(\frac{4}{11}\)

A trapezoid is a quadrilateral with one set of parallel sides.

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.

4y - 5 = \( \frac{y}{-8} \)
-8 x (4y - 5) = y
(-8 x 4y) + (-8 x -5) = y
-32y + 40 = y
-32y + 40 - y = 0
-32y - y = -40
-33y = -40
y = \( \frac{-40}{-33} \)
y = 1\(\frac{7}{33}\)

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.

-9y + 6 > -5 + 8y
-9y > -5 + 8y - 6
-9y - 8y > -5 - 6
-17y > -11
y > \( \frac{-11}{-17} \)
y > \(\frac{11}{17}\)