Answer:
The solution set is (-8, -29) (Answer E)
Step-by-step explanation:
Changing the given info into equations, we obtain:
a - b = 21 and
5a - 2b = 18
Let's use elimination by addition/subtraction. Multiply the first equation by -5 to obtain
-5a + 5b = -105
and then add this result to the second equation:
-5a + 5b = -105
5a - 2b = 18
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3b = - 87
Dividing both sides by 3 yields:
b = -87/3 = -29
Now substitute -29 for b in a - b = 21
a - (-29) = 21, or a + 29 = 21. Then a = -8.
The solution set is (-8, -29) (Answer E)
