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

c + y = -4
y = -4 - c

then substitute the result (-4 - 1c) into the second equation:

5c + 8(-4 - c) = -7
5c + (8 x -4) + (8 x -c) = -7
5c - 32 - 8c = -7
5c - 8c = -7 + 32
-3c = 25
c = \( \frac{25}{-3} \)
c = -8\(\frac{1}{3}\)

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).

A cylinder is a solid figure with straight parallel sides and a circular or oval cross section with a radius (r) and a height (h). The volume of a cylinder is π r²h and the surface area is 2(π r²) + 2π rh.

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.

9a⁹ + 7a⁹ = 16a⁹

A monomial contains one term, a binomial contains two terms, and a polynomial contains more than two terms.