Question

Evaluate b – 2a – c for a = –3, b = 9, and c = –6.

Answer 1

b – 2a – c

9 - 2(-3) - (-6) = ?

9 - 2(-3) - (-6) = 21

Answer 2

Okay, so, first, we plug in each number for each variable, for example, in your equation:

b - 2a - c
_________
a = -3

b = 9

c = -6
_________

Okay, so now, we plug in each number for each variable:

9 - 2( -3 ) - ( -6 )

Now, we do PEMDAS:

Parentheses
Exponents
Multiplication
Division
Addition
Subtraction

-2 times -3 equals 6, because, two negatives make a positive:

9 + 6 - ( -6)

think of the - before the parentheses, as a negative one, and, again, two negatives make a positive, so, -1 times -6 equals 6

9 + 6 + 6

Now, we solve by addition, because they are all like terms:

9 + 6 + 6
15 + 6
________
21

The answer is 21.
_____________________________________________________

I hope this helps!