To solve this equation, replace the variables with the values given and then solve the now variable-free equation. (Remember order of operations, PEMDAS, Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.)

7c(c - y)
7(8)(8 + 2)
7(8)(10)
(56)(10)
560

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)(6ab) - (4a²)(7b)
(9 x 6)(a x a x b) - (4 x 7)(a² x b)
(54)(a¹⁺¹ x b) - (28)(a²b)
54a²b - 28a²b
26a²b

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

2b + y = -4
y = -4 - 2b

then substitute the result (-4 - 2b) into the second equation:

-4b + 7(-4 - 2b) = -4
-4b + (7 x -4) + (7 x -2b) = -4
-4b - 28 - 14b = -4
-4b - 14b = -4 + 28
-18b = 24
b = \( \frac{24}{-18} \)
b = -1\(\frac{1}{3}\)

The formula for area is πr². Radius is circle \( \frac{diameter}{2} \):

r = \( \frac{d}{2} \)
r = \( \frac{10}{2} \)
r = 5
a = πr²
a = π(5²)
a = 25π

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.