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.

(8a)(7ab) - (7a²)(4b)
(8 x 7)(a x a x b) - (7 x 4)(a² x b)
(56)(a¹⁺¹ x b) - (28)(a²b)
56a²b - 28a²b
28a²b

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

6c + z = -3
z = -3 - 6c

then substitute the result (-3 - 6c) into the second equation:

8c - 9(-3 - 6c) = -1
8c + (-9 x -3) + (-9 x -6c) = -1
8c + 27 + 54c = -1
8c + 54c = -1 - 27
62c = -28
c = \( \frac{-28}{62} \)
c = -\(\frac{14}{31}\)

The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

x² + 5x - 1 = x + 4
x² + 5x - 1 - 4 = x
x² + 5x - x - 5 = 0
x² + 4x - 5 = 0

Next, factor the quadratic equation:

x² + 4x - 5 = 0
(x - 1)(x + 5) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (x - 1) or (x + 5) must equal zero:

If (x - 1) = 0, x must equal 1
If (x + 5) = 0, x must equal -5

So the solution is that x = 1 or -5

The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 4 x 2 = \( \frac{8}{2} \) = 4

The area of a rectangle is equal to its length x width:

a = l x w
a = a x b
a = 2 x 3
a = 6