Answer:
D. 10^10
Step-by-step explanation:
Multiplying numbers with exponents rule : 
explanation of rule : we simply keep the bases the same and add the exponents.
10^3 • 10^7
keep the base as 10 and add the exponents

Keep in mind that this only works when the bases are the same.
Answer:
-9,-21
Step-by-step explanation:
let the numbers be x and y and x>y
x-y=12
y=2x-3
x-(2x-3)=12
x-2x+3=12
-x=12-3
-x=9
x=-9
y=2(-9)-3=-18-3=-21
Answer:
c) 48
Step-by-step explanation:
1/3(24)(6)
24*6= 144
144*1/3= 48
hope this helps!
The denominator of the second fraction is the difference of squares, so can be factored using the formula for that.
(n^2 -4) = (n -2)(n +2)
Now, you will note that the second fraction has a numerator that is equal to one of the factors in the denominator. In other words, the whole fraction can be simplified to ...
(n +2)/((n +2)(n -2)) = 1/(n -2) . . . . with the restriction n≠-2
This reduced form of the fraction has the same denominator as the first fraction, so you can say that the lowest common denominator is that: (n -2).
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If there is some reason you don't want to reduce the second fraction, the lowest common denominator will be (n -2)(n +2).