What would the equation look like when the line is perpendicular to x+2y=10 and has a y-intercept of -10

Eq1: x + 2y = 10.

m1 = -A/B = -1/2

The slope of the 2nd line = the negative reciprocal of m1:
m2 = -(-2/1) = 2.

Y = mx + b
Eq2: Y = 2x - 10 or 2x - y = 10