3 years ago

Why is -9an acceptable answer to the equation x2=81 ?

Mathematics

2 answers:

Arte-miy333 [17]3 years ago

8 0

Answer:

X=9 or x=-9

Step-by-step explanation:

X^2=81

Can be written as

x^2-81=0

Factorize by the property:

a^2-b^2=(a-b)(a+b)

So the expression becomes:

(x-9)(x+9)=0

Therefore, either x-9=0or x+9=0

Then the solutions are x=9 or x=-9

Zielflug [23.3K]3 years ago

4 0

Step-by-step explanation:

Because square of a negative number gives a positive number, that's why - 9 is an acceptable answer to the equation $x^2 = 81$

You might be interested in

Rearrange x = 3g + 2 to make g the subject

lord [1]

Answer:

$g=\frac{x}{3} -\frac{2}{3}$

Step-by-step explanation:

You divide 3 from both sides leaving you with g=(x/3)-(2/3)

Please mark my answer as brainlyest.

7 0

3 years ago

What happens to the graph of y = |x| when the equation changes to y |x-9|?

zhenek [66]

Answer: The graph will move 9 spaces to the right.

7 0

3 years ago

What is the difference when the sum of 12 and (-6) is subtracted from the quotient of (-21) and 3?

Bumek [7]

12+(-6)-[(-21)/3]
=6-(-7)=6+7=13

6 0

3 years ago

Find the length of the segment indicated. A. 16.4 B. 11.4 C. 12.1 D. 13.3

kykrilka [37]

using Pythagorean triplet

$\\ \sf\longmapsto P^2=H^2-B^2$

$\\ \sf\longmapsto x^2=19.6^2-15.4^2$

$\\ \sf\longmapsto x^2=384.16-237.16$

$\\ \sf\longmapsto x^2=147$

$\\ \sf\longmapsto x=\sqrt{147}$

$\\ \sf\longmapsto x=12.1$

4 0

3 years ago

A=1/2h(b+c) solve for h

pogonyaev

1) Multiply both sides of the equation by 2:

2(A)=2[1/2h(b+c)
2A=2/2h(b+c)
2A=1h(b+c)
2A=h(b+c)

2) Divide both sides of the equation by (b+c):
(2A)/(b+c)=[h(b+c)]/(b+c)
2A/(b+c)=h
h=2A/(b+c)

Answer: $h=2 \frac{A}{(b+c)}$

5 0

3 years ago