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3 years ago

R-12 evaluate if r= 7

Mathematics

2 answers:

Irina18 [472]3 years ago

7 0

The answer should be-5

lara [203]3 years ago

4 0

r-12
substitute in r=7
so 7-12 = -5

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3 years ago

Which is not a solution of the inequality?

Soloha48 [4]

Answer:

Answer= -4 hope it helps

4 0

3 years ago

FIND THE AREA AND PERIMETER PLEASE

baherus [9]

Answer:

Area = 70 Perimeter = 50

Step-by-step explanation:

I will begin with area. I can find the area of each figure, then add the areas.

3 • 18 = 54

4 • 4 = 16

Area = 70

For perimeter, I will add the given lengths.

3 + 18 + 7 + 4 + 4 + 14

Perimeter = 50

8 0

3 years ago

Read 2 more answers

-1/6 + 2/3 ( 9 + - 3/4) + - 1/2

Liono4ka [1.6K]

First simplify the section in the parenthesis.
-1/6 + 2/3(8 1/4) + -1/2
Then multiply 2/3 by 8 1/4.
-1/6 + 5 1/2 + -1/2
Add -1/2 to 5 1/2.
-1/6 + 5
Add 5 to -1/6.
4 5/6 is the fully simplified answer.
Hope this helps!

7 0

3 years ago

Please Help!!

Genrish500 [490]

Given

$a\sqrt{x+b}+c=d$

we have

$\sqrt{x+b}=\dfrac{d-c}{a}$

Squaring both sides, we have

$x+b=\dfrac{(d-c)^2}{a^2}$

And finally

$x=\dfrac{(d-c)^2}{a^2}-b$

Note that, when we square both sides, we have to assume that

$\dfrac{d-c}{a}>0$

because we're assuming that this fraction equals a square root, which is positive.

So, if that fraction is positive you'll actually have roots: choose

$a=1,\ b=0,\ c=2,\ d=6$

and you'll have

$\sqrt{x}+2=6 \iff \sqrt{x}=4 \iff x=16$

Which is a valid solution. If, instead, the fraction is negative, you'll have extraneous roots: choose

$a=1,\ b=0,\ c=10,\ d=4$

and you'll have

$\sqrt{x}+10=4 \iff \sqrt{x}=-6$

Squaring both sides (and here's the mistake!!) you'd have

$x=36$

which is not a solution for the equation, if we plug it in we have

$\sqrt{x}+10=4 \implies \sqrt{36}+10=4 \implies 6+10=4$

Which is clearly false

7 0

3 years ago