PLEASEE HELP MEEE ITS A TEST, 20 POINTS

How do you use the additive inverse to evaluate an expression that uses subtraction in a full sentence

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.

James adds two numbers a + b. sally adds the same two numbers but reverse the order b + a what property of addition assures us that james and sally will get the same sum