Write 8x+4y=20 in function form
Writing a an equation in function form is simply expressing y values in terms of x. In other words when you substitute a particular value for x, you get a particular value for y.
so
8x + 4y = 20
4y = 20 - 8x
y = (20-8x)/4 or y = (20-8x)/4 or y = f(x) = 2(10-4x)/4 = (10-4x)/2 = 5 - 2x = -2x+5
check your answer with a sample values say with a point that solves the equation or a point on the line.....see below....
(2,1)
8(2) + 4(1) = 20......16 + 4 = 20...check.......y=-2(2) + 5 = -4 +5 =1....x=2, y=1...checks....so f(x)=-2x+5
another quick check are the intercepts.....y (x=0)....or x (y=0)
8 (0) + 4 (5) = 20.....(0,5).......y=f(x) = -2 (0) + 5...x = 0..y=5 so again the function checks so
8x + 4y = 20.....is also written as the function y= f(x)= -2x + 5