Answer:
(B) The exponents should be subtracted by the quotient rule of exponents
Step-by-step explanation:
Let's examine how this was solved.

He first rose everything in the parentheses to the second power, which is just multiplying all the exponents by 2. This is correct.

He then combined the numerator exponents. Exponent rules say that
, so he should have ended up with
, which he did. This is correct.

Now, what he did in the final step is wrong. He added the exponents. However, exponent rules tell us that when we have
, it equals
.

So the final answer should have been 
Hope this helped!
Answer:
(1,2)
Step-by-step explanation:
Substitution:
x + 2y = 5 Solve for x
x = -2y + 5 Substitute -2y + 5 in for x in the second equation
4x - 12y = -20
4(-2y + 5) - 12y = -20 Distribute the 4
-8y + 20 - 12 y = -20 Combine the y term
-20y + 20 = -20 Subtract 20 from both sides
-20y = -40 Divide both sides by -20
y = 2
Plug y into either of the 2 original equations to get x.
x + 2y = 5
x + 2(2) = 5
x + 4 = 5
x = 1
The answer is (2,1).
Elimination:
x + 2y = 5 4x - 12y = -20. We want to eliminate with the x or the y. I am going to eliminate the x's that means that I have to multiply the first equation all the way through by -4
(-4)(x + 2y) = (5) (-4) That makes the equivalent expression
-4x - 8y = -20 I will add that to 4x - 12y = -20
<u>4x - 12y = -20</u>
0x -20y = -40
-20y = -40
y = 2. Plug 2 into either the 2 original equation to find x. This time I will select the second original equation to find x.
4x -12y = -20
4x - 12(2) = -20
4x - 24 = -20
4x = 4
x = 1
5c+4b=profit (extra words because i need 20 characters to submit answer)
Answer:
Yup that's a scientific number alright.
If y=12 when x=6, then y=36 when x=18 by the equation y=2x.