6. If the x intercept is a then (a,0) is on the line. If y-intercept is b then (0,b) is on the line. Now you have two points of the line and can get its formula. The slope between thse points is m=(0−b)(a−0)=−b/a. So the equation of line is y=mx+b=−bx/a+b. Now rearrange as y+bx/a=b divide by b to get y/b+x/a=1
Sadly I can't get eight right now but once I do I will edit this.
