Answer:
(b) 320
Explanation:
You want the value of the expression 2a² - 8ab - √b if a=-7 and b=4.
Evaluation
Put the numbers where the corresponding variables are, and do the arithmetic.
2(-7)² -8(-7)(4) -√4
= 2(49) +224 -2
= 98 +224 -2
= 322 -2
= 320
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Additional comment
Once you realize √4 = 2, you know this is the sum of even numbers, so cannot evaluate to an odd number. This leaves only one viable choice: 320.