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

-7c + z = -1
z = -1 + 7c

then substitute the result (-1 - -7c) into the second equation:

-6c + 8(-1 + 7c) = 8
-6c + (8 x -1) + (8 x 7c) = 8
-6c - 8 + 56c = 8
-6c + 56c = 8 + 8
50c = 16
c = \( \frac{16}{50} \)
c = \(\frac{8}{25}\)

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.

(4a)(7ab) + (5a²)(5b)
(4 x 7)(a x a x b) + (5 x 5)(a² x b)
(28)(a¹⁺¹ x b) + (25)(a²b)
28a²b + 25a²b
53a²b

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

6a + 2a = 8a

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.

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:

y² + 8y + 8 = y - 2
y² + 8y + 8 + 2 = y
y² + 8y - y + 10 = 0
y² + 7y + 10 = 0

Next, factor the quadratic equation:

y² + 7y + 10 = 0
(y + 2)(y + 5) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y + 2) or (y + 5) must equal zero:

If (y + 2) = 0, y must equal -2
If (y + 5) = 0, y must equal -5

So the solution is that y = -2 or -5