The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

a² - 4a + 9 = 5a + 1
a² - 4a + 9 - 1 = 5a
a² - 4a - 5a + 8 = 0
a² - 9a + 8 = 0

Next, factor the quadratic equation:

a² - 9a + 8 = 0
(a - 1)(a - 8) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (a - 1) or (a - 8) must equal zero:

If (a - 1) = 0, a must equal 1
If (a - 8) = 0, a must equal 8

So the solution is that a = 1 or 8

To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses:

(y + 3)(y + 7)
(y x y) + (y x 7) + (3 x y) + (3 x 7)
y² + 7y + 3y + 21
y² + 10y + 21

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 b so solve the first equation in terms of x:

-b + x = -1
x = -1 + b

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

4b + 4(-1 + b) = -8
4b + (4 x -1) + (4 x b) = -8
4b - 4 + 4b = -8
4b + 4b = -8 + 4
8b = -4
b = \( \frac{-4}{8} \)
b = -\(\frac{1}{2}\)

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 1 + 2 + 3 + 4
p = 10