Question

How do you evaluate `12a+3b` if `a=-1` and `b=-7`?

Answer 1

`-33`

Explanation:

substitute a = - 1 and b = - 7 into the expression.

`(12xxcolor(blue)(-1))+(3xxcolor(red)(-7))`

now evaluate each bracket.

`=-12+(-21)=-12-21=-33`