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

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

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

-2b - 4(-8 + 4b) = 6
-2b + (-4 x -8) + (-4 x 4b) = 6
-2b + 32 - 16b = 6
-2b - 16b = 6 - 32
-18b = -26
b = \( \frac{-26}{-18} \)
b = 1\(\frac{4}{9}\)

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.

c + 2 < \( \frac{c}{-5} \)
-5 x (c + 2) < c
(-5 x c) + (-5 x 2) < c
-5c - 10 < c
-5c - 10 - c < 0
-5c - c < 10
-6c < 10
c < \( \frac{10}{-6} \)
c < -1\(\frac{2}{3}\)

To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses:

(y - 7)(y - 6)
(y x y) + (y x -6) + (-7 x y) + (-7 x -6)
y² - 6y - 7y + 42
y² - 13y + 42

You can only add or subtract monomials that have the same variable and the same exponent. For example, 2a + 4a = 6a and 4a² - a² = 3a² but 2a + 4b and 7a - 3b cannot be combined. However, you can multiply and divide monomials with unlike terms. For example, 2a x 6b = 12ab.

The perimeter of a triangle is the sum of the lengths of its sides:

p = x + y + z
p = 11cm + 15cm + 14cm = 40cm