Solve this equation using an algebraic method: (x + 4)( x - 4) = 9

Mathematics

2 answers:

Mila [183]3 years ago

8 0

(x+4)(x-4)=9 carry out multiplications on left side

x^2-16=9 add 16 to both sides

x^2=25 take the square root of both sides

x=√25

x=±5

So there are two solutions x=-5 and 5

Svetradugi [14.3K]3 years ago

3 0

This is the answer that i was going to upload :
the answer is +5(or)-5 because of root

You might be interested in

Which list shows the numbers in order from largest to smallest?

Aleksandr-060686 [28]

Answer:

Step-by-step explanation:

10/3 = 3.33

3.3 = 3.3

pie =3.14

square root of 8 =2.8

4 0

3 years ago

What is the rate of change between the interval of x = 3 pi over 2 and x = 2π?

galina1969 [7]

Check the picture below.

$\bf slope = m = \cfrac{rise}{run} \implies 
\cfrac{ f(x_2) - f(x_1)}{ x_2 - x_1}\impliedby 
\begin{array}{llll}
average~rate\\
of~change
\end{array}\\\\
-------------------------------\\\\
\begin{cases}
x_1=\frac{3\pi }{2}\\
x_2=2\pi 
\end{cases}\implies \cfrac{f(2\pi )-f\left( \frac{3\pi }{2} \right)}{2\pi -\frac{3\pi }{2} }\implies \cfrac{3-1}{\frac{4\pi -3\pi }{2}}\implies \cfrac{2}{\quad \frac{\pi}{2}\quad }\implies \cfrac{4}{\pi }$