Gabrielle is 12 years younger than Mikhail. The sum of their ages is 76 . What is Mikhail's age?
2 answers:
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Answers:
- b = -19
- b = -11
- b = -9
- b = 19
- b = 11
- b = 9
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Explanation:
Here are all the ways to multiply to 18 when using integers only:
- -1*(-18) = 18
- -2*(-9) = 18
- -3*(-6) = 18
- 1*18 = 18
- 2*9 = 18
- 3*6 = 18
Sum each pair of factors to find out a possible value of b.
- -1 + (-18) = -19
- -2 + (-9) = -11
- -3 + (-6) = -9
- 1 + 18 = 19
- 2 + 9 = 11
- 3 + 6 = 9
Therefore, the possible values of b are
- b = -19
- b = -11
- b = -9
- b = 19
- b = 11
- b = 9
which are the final answers.
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An example:
Let's say b = 11. This would mean becomes
It would factor to since it was stated earlier that:
2+9 = 11
2 * 9 = 18
You can use the FOIL rule, distributive property, or the box method to confirm that is a true equation for all real numbers x.
This same idea applies for the other values of b.
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If you're curious why this works, consider multiplying the two factors (x+p) and (x+q)
Use the FOIL rule to get
The middle term has the components add to the coefficient, while those same two components multiply to get the last term. This is why when factoring we're looking for two numbers that multiply to 18, and also add to the value of b (which in the case of the last example was 11).
We know that the load is 8713 lbs.
The total weight (truck + load) is 17200 lb.
Then, we can calculate the weight of the empty truck as:
Answer: the empty truck's weight is 8487 lb.
T: empty truck's weight
W: total weight (loaded truck's weight)
L: Load
The equation is:
T = W - L