What does "x" equal when

Find the equation of the line that goes through the points (4, –1) and (2, –5). use slope formula,equation,to find the slope of a line that passes through the points. m = use slope-intercept form, y = mx + b, to find the y-intercept (b) of the line. b = write the equation in slope-intercept form, y = mx + b.

Complete the solution of the equation. find the value of y when x equals to 6 4x+y=20

A25- foot ladder leans against a building and reaches a point of 23.5 feet above the ground .find the angle that the ladder makes with the building