Write an equation of the line that passes through (7,10) and is perpendicular to the line y=1/2x-9.

The slope is - 2 because the slope of a perpendicular line is the opposite fraction (flip numerator and denominator) and the opposite sign (negative/positive).

Use y=mx+b to find out the y intercept.

10=-2 (7) + b

10=-14+b

24=b

Your equation would be

y=-2x+24