Problem 3
The constant term is 290. This is the term that stays the same no matter what the value of 'a' happens to be. Contrast this with the variable term 2.50a which changes if 'a' changes (hence the name "variable" for "vary" or "change")
If Mike sold 0 accessories, then a = 0 and the expression would be
2.50*a + 290 = 2.50*0 + 290 = 290
Selling 0 accessories leads to $290. This is the amount he is guaranteed with the 2.50a portion being additional money to motivate him to sell more.
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Answer: Choice (3) 290, amount he is guaranteed
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Problem 4
Plug y = 0 into the equation. Solve for x
9x - 14y = -3
9x - 14*0 = -3 .... replace y with 0
9x - 0 = -3
9x = -3
9x/9 = -3/9 ... divide both sides by 9
x = -3/9
x = -1/3
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Answer: Choice (3) which is -1/3