# SOLUTION: I do not understand how to solve for m. I know that this should be y=mx+b but I cant remember how to do these problems. I have my math final on Monday night and I am really needin

Algebra ->  -> SOLUTION: I do not understand how to solve for m. I know that this should be y=mx+b but I cant remember how to do these problems. I have my math final on Monday night and I am really needin      Log On

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 Question 249107: I do not understand how to solve for m. I know that this should be y=mx+b but I cant remember how to do these problems. I have my math final on Monday night and I am really needing help on how to solve these the question I am showing is "Write an equation of the line that passes through the point (-3,-1) and is perpindicular to the line x + 3y = 9. Can someone help me with this?Answer by stanbon(60778)   (Show Source): You can put this solution on YOUR website!Write an equation of the line that passes through the point (-3,-1) and is perpendicular to the line x + 3y = 9. ------------------ Find the slope of the given line: 3y = -x + 9 y = (-1/3)x + 3 -------------------- Slope of the given line is -1/3. ---- Note: Any line perpendicular to the given line must have slope -3. ---------------- Your Problem: You want the equation of the line that has slope -3 and passes thru (-3,-1). ------------------------ Form of the line is y = mx + b; you need to find "m" and "b": m = -3 --- -1 = -3*-3 + b -1 = 9 + b b = -10 ----- Equation: y = -3x - 10 =============================== Cheers, Stan H.