Answer: Hope this helps!
Left to right - Q1 - Q5
1,500, 1,250, 0.25, 105, 25%
Step-by-step explanation:
Q1 - 15,000 * 0.02 * 5 = 1,500
Q2 - 25,000 * 0.01 * 5 = 1,250
Q3 - 20 - ((6 * 1) + (3 * 0.75) + (10 * 0.35) + (4 * 2)) = 0.25, 25 cents
Q4 - 30x + 1,000 = 4,200 (X = 107) Approximately 105 jobs
Q5 - 1,584 / (32 * 66) = 0.75 (75%) 100% - 75% = 25%
Let the numbers be x and y. Then xy = -30 and x+y = -3.
Solve xy = -30 for y: y = -30/x
subst. -30/x for y in x+y= -3: x - 30/x = -3
Multiply all 3 terms by x: x^2 - 30 = -3x, so x^2 + 3x - 10 = 0
Solve this quadratic equation for x. x: {-5, 2}
If x = -5, then x+y = -3 becomes -5 + y = -3, and y = 2.
You should check to determine whether x=2 is also correct. If it is, what is the corresponding y value?
Answer: 
Step-by-step explanation:
We know that the general form of the exponential decay formula is
, where y is final amount remaining after t time, A is the original amount and r is the rate of decay
Now, the ratio of strontium-90 remaining, p , as a function of years, t , since the nuclear accident. 
Hence, the ratio of remaining since the nuclear accident is
As a = 0 , there is no sign . Its only 0. Thus the answer is (c)
