[tex]\text{Slope- intercept form is y =mx+c, where m is the slope and c is the y-intercept.}\\ \\\textbf{1)}\\\\~~~~~3x = -8+y\\\\\implies y = 3x +8\\\\\textbf{2)}\\\\~~~~~9=3x+3y\\\\\implies 3y= 9-3x\\\\\implies y= \dfrac 13(9-3x)\\\\\implies y= 3-x\\\\\implies y= -x+3\\\\\textbf{3)}\\\\~~~~~~4y-10 = 20x\\\\\implies 4y = 20x +10\\\\\implies 2y = 10x +5\\\\\implies y = \dfrac 12(10x +5)\\\\\implies y= 5x +\dfrac 52[/tex]