Please help)Simplify: (r – 7)(r + 7)

Mathematics

2 answers:

PtichkaEL [24]4 years ago

5 0

Answer:

Im pretty sure the answer is

C) r^2 - 49

Step-by-step explanation:

Serggg [28]4 years ago

4 0

Answer:

r^2-49

Step-by-step explanation:

r^2+7r-7r-49 || r^2-49

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4x^2 = 92 + 7x solve the equation using the guadratic formula, show all work

katovenus [111]

$4x^2=92+7x\ \ \ \ |-4x^2\\\\-4x^2+7x+92=0\\\\a=-4;\ b=7;\ c=92\\\\b^2-4ac=7^2-4\cdot(-4)\cdot92=49+1472=1521\\\\\sqrt{b^2-4ac}=\sqrt{1521}=39\\\\x_1=\dfrac{-b-\sqrt{b^2-4ac}}{2a};\ x_2=\dfrac{-b+\sqrt{b^2-4ac}}{2a}\\\\x_1=\dfrac{-7-39}{2\cdot(-4)}=\dfrac{-46}{-8}=\dfrac{23}{4}\\\\x_2=\dfrac{-7+39}{2\cdot(-4)}=\dfrac{32}{-8}=-4$

$\text{Answer:}\ A.\ \left\{\dfrac{23}{4};\ -4\right\}$

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4 years ago

The original selling price of a shirt was $45.

marissa [1.9K]

Given:

The original selling price of a shirt was $45.

In a sale, the shirt is reduced to $32.50.

To find:

The percentage reduction.

Solution:

We know that,

$\text{Percentage reduction}=\dfrac{\text{Original value - Reduced value}}{\text{Original value}}\times 100$