The sum of the interior angles of a triangle is 180°:
180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 34° - 51° = 95°

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

-8b + z = -4
z = -4 + 8b

then substitute the result (-4 - -8b) into the second equation:

8b - 7(-4 + 8b) = 9
8b + (-7 x -4) + (-7 x 8b) = 9
8b + 28 - 56b = 9
8b - 56b = 9 - 28
-48b = -19
b = \( \frac{-19}{-48} \)
b = \(\frac{19}{48}\)

The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².

A parallelogram is a quadrilateral with two sets of parallel sides. Opposite sides (a = c, b = d) and angles (red = red, blue = blue) are equal. The area of a parallelogram is base x height and the perimeter is the sum of the lengths of all sides (a + b + c + d).

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.

-7c - 2 < \( \frac{c}{5} \)
5 x (-7c - 2) < c
(5 x -7c) + (5 x -2) < c
-35c - 10 < c
-35c - 10 - c < 0
-35c - c < 10
-36c < 10
c < \( \frac{10}{-36} \)
c < -\(\frac{5}{18}\)