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.)

8b(b - y)
8(-7)(-7 - 9)
8(-7)(-16)
(-56)(-16)
896

An isosceles triangle has two sides of equal length. An equilateral triangle has three sides of equal length. In a right triangle, two sides meet at a right angle.

The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:

x² - 10x + 21 = 0
(x - 3)(x - 7) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (x - 3) or (x - 7) must equal zero:

If (x - 3) = 0, x must equal 3
If (x - 7) = 0, x must equal 7

So the solution is that x = 3 or 7

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

-3a + x = 1
x = 1 + 3a

then substitute the result (1 - -3a) into the second equation:

-a + 7(1 + 3a) = 9
-a + (7 x 1) + (7 x 3a) = 9
-a + 7 + 21a = 9
-a + 21a = 9 - 7
20a = 2
a = \( \frac{2}{20} \)
a = \(\frac{1}{10}\)

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)(4ab) + (8a²)(3b)
(7 x 4)(a x a x b) + (8 x 3)(a² x b)
(28)(a¹⁺¹ x b) + (24)(a²b)
28a²b + 24a²b
52a²b