Evaluate -2x  if     x = 10

Evaluate when a = 15:
2(a - 5) + 2

Evaluate the expression.   Let g = 3    h = 9 
4h + 2g + 4

3r + 2e; r = 3  e = 2

What is the value of the expression
x² + y² + x - y 
when x = -1 and y = 3

evaluate bc + 5a  
when  a = 3, b = 4, and c = -6

9a - ab + 5b    
if a = 2 and b = 7

2x + 5(y - 1) when x=8 and y=5