1) B irrational
2) B sometimes because a negative integer is not a whole number
3) C irrationals
4) C and D are whole numbers
5) C irrational
6) D 7/10 because a rational number is always a faction
7) C rational numbers
8) D real and rational
9) D rational, real, whole number
10) A integers
Answer:
C. Solving this equation results in the statement –48 = 48. Because this is a false statement, the equation has no solution.
I think a) would be the answer. I proceeded by elimination: the domaine of the function goes from 3 and continues to infinity, so that leaves with a) and b) as possible answers. Both have the same range and both of their functions reflect over the x axis, so we have to compare the two answer by looking at the position of the function in the graph. The function is in the first quadrant (top right corner), so the position of the function has to be at our right, which leads us to a).
C) (0.85 + x/100)(250+145) does not give the correct answer.
Explanation
A) works; adding the two costs together is 250+145=395. We multiply this by 0.85 because 100%-15%=85%=0.85. We also have x% tax, which is represented by x/100, added to 100% of the value, or 1.00. Altogether this gives us
395(0.85)(1+x/100) = 395(0.85 + (0.85x/100)) = 395(0.85) + 395(0.85x/100)
= 395(0.85) + 395(0.0085x)
B) works; we have 250+145 for the original price; we have 85% = 0.85 of the value; we also have 100% + x%, which is (100+x)/100.
C) does not work; (0.85+x/100)(395) does not take into consideration that you are finding the tax after taking the 85%. This will simplify out to
0.85*395 + (x/100)(395) = 335.75 + 395x/100 = 335.75 + 3.95x, which is too much.
D) works; simplifying the expression from A, we have 395(0.85) + 395(0.0085x) = 335.75 + 3.3575x.
