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) + (4a²)(6b)
(8 x 7)(a x a x b) + (4 x 6)(a² x b)
(56)(a¹⁺¹ x b) + (24)(a²b)
56a²b + 24a²b
80a²b

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

-3a + z = -3
z = -3 + 3a

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

-8a - 8(-3 + 3a) = 7
-8a + (-8 x -3) + (-8 x 3a) = 7
-8a + 24 - 24a = 7
-8a - 24a = 7 - 24
-32a = -17
a = \( \frac{-17}{-32} \)
a = \(\frac{17}{32}\)

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.

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)(6ab) - (8a²)(5b)
(4 x 6)(a x a x b) - (8 x 5)(a² x b)
(24)(a¹⁺¹ x b) - (40)(a²b)
24a²b - 40a²b
-16a²b

An equation is two expressions separated by an equal sign. The key to solving equations is to 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.