find angle depression lighthouse 112m above sea level to boat that is at horizontal distance 1.5km from lighthouse

What is the point-slope form of theequation for the line with a slope of-2 that passes through (1, 4)? a y + 1 = -2(x + 4)b y-1=-2(x-4)c y + 4 = -2(x + 1)d y - 4 = -2(x - 1)

The radical equation 2+√2x-3 = √x+7 has a solution set [x= a0} and an extraneous root x = a1.

How do you use the elimination method for this question? explain, because i really want to understand!