Answer:
21
Step-by-step explanation:
Given
b - 4a ← substitute a = 6 and b = 45 into the expression
45 - 4(6) = 45 - 24 = 21
When you plug the values in the expression becomes 45 - 4(6). Following the order of operations multiply 4(6) first. Now the equation is 45 - 24. Subtract these numbers to get 21.
