Find the area of the figure

Which values for a and b will create infinitely many solutions for this system of equations? ax-y=8 2x+y=b

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.

What is the value of n in the equation -1/2(2n+4)+6=-9+4(2n+1)