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.

(9a)(2ab) + (3a²)(6b)
(9 x 2)(a x a x b) + (3 x 6)(a² x b)
(18)(a¹⁺¹ x b) + (18)(a²b)
18a²b + 18a²b
36a²b

A circle is a figure in which each point around its perimeter is an equal distance from the center. The radius of a circle is the distance between the center and any point along its perimeter. A chord is a line segment that connects any two points along its perimeter. The diameter of a circle is the length of a chord that passes through the center of the circle and equals twice the circle's radius (2r).

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.

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

-5a + z = -5
z = -5 + 5a

then substitute the result (-5 - -5a) into the second equation:

4a + 2(-5 + 5a) = 3
4a + (2 x -5) + (2 x 5a) = 3
4a - 10 + 10a = 3
4a + 10a = 3 + 10
14a = 13
a = \( \frac{13}{14} \)
a = \(\frac{13}{14}\)