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

-4c + z = -3
z = -3 + 4c

then substitute the result (-3 - -4c) into the second equation:

-9c + 7(-3 + 4c) = 4
-9c + (7 x -3) + (7 x 4c) = 4
-9c - 21 + 28c = 4
-9c + 28c = 4 + 21
19c = 25
c = \( \frac{25}{19} \)
c = 1\(\frac{6}{19}\)

The coordinate grid is composed of a horizontal x-axis and a vertical y-axis. The center of the grid, where the x-axis and y-axis meet, is called the origin.

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.

8a - 2a = 6a

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.

(7a)(3ab) + (7a²)(6b)
(7 x 3)(a x a x b) + (7 x 6)(a² x b)
(21)(a¹⁺¹ x b) + (42)(a²b)
21a²b + 42a²b
63a²b

A trapezoid is a quadrilateral with one set of parallel sides.