Mathematics: PL IM DOING MY MATH FINAL - SHOW WORK Rewrite the equation by completing the square. x^2+18x-8=0

Perimeter is 9+3.5+9+3.5= 25found the answer by adding all sides...

PL IM DOING MY MATH FINAL - SHOW WORK Rewrite the

pstiner

26.06.2021

x = - 9 ± √89

Step-by-step explanation:

Quadratic formula:

$x=\frac{-b±\sqrt{b^{2}-4abc } }{2a}$

Ignore the A after the -b, wouldn't let me type it correctly.

x² + 18x - 8 = 0

With the formula.

a = 1

b = 18

c = - 8

$x=\frac{-18±\sqrt{18^{2}-4(1(-8))}}{2(1)}$

Ignore the A again and for the rest of the explanation.

$x=\frac{-18±\sqrt{18^{2}-4(1(-8))}}{2(1)}$

$x=\frac{-18±\sqrt{324-4(1(-8))}}{2(1)}$

$x=\frac{-18±\sqrt{324+32}}{2(1)}$

$x=\frac{-18±\sqrt{356}}{2(1)}$

Now we will factorize the √356.

$x=\frac{-18±\sqrt{2}\sqrt{2}\sqrt{89}}{2(1)}$

$x=\frac{-18±2\sqrt{89}}{2}$

Separate into two equations.

One with addition and the other with subtraction.

$x=\frac{-18+2\sqrt{89}}{2}\\x=\frac{-18-2\sqrt{89}}{2}$

Solve:

$x=\frac{-9+\sqrt{89}}{2}\\\\x=\frac{-9-\sqrt{89}}{2}$

± is a mathematical symbol which represents addition and/or subtraction.

x = - 9 ± √89

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