# SOLUTION: How do I solve 5x+4=7 and x-3y=9. I have to find the graph

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 Click here to see ALL problems on Linear-systems Question 149688: How do I solve 5x+4=7 and x-3y=9. I have to find the graphAnswer by ankor@dixie-net.com(15661)   (Show Source): You can put this solution on YOUR website!How do I solve 5x+4y=7 and x-3y=9. : We can use the 2nd equation for substitution: x - 3y = 9 which is: x = 3y + 9 : Substitute (3y+9) for x in the 2nd equation. find y: 5x + 4y = 7 : 5(3y+9) + 4y = 7 : 15y + 45 + 4y = 7 : 15y + 4y = 7 - 45 : 19y = -38 y = y = -2 : Find x, substitute -2 for y, in equation: x = 3y + 9 x = 3(-2) + 9 x = +3 : Check solution in the 1st original equation; 5x + 4y = 7 5(3) + 4(-2) = 15 - 8 = +7 : : I have to find the graph : Arrange equation into the general y= form 5x + 4y = 7 4y = 7 - 5x y = - x : x - 3y = 9 -3y = 9 - x y = + y = - 3 : Plot these two equations; : Note the point of intersection is x=3, y=-2, our solution