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(y=mx+ b) (Ax+By=C)
¨ First: Make sure that the equation you are given
is in the correct form: y= mx+b
(where m= slope, b= y intercept, and the y & x remain variables.)
¨The rules of standard form: Ax+ By=C
(where A, B, and C are all numerical values and x & y remain variables.)
W A must always be positive.
W Neither A nor B can be fractions.
W What you do to one side you must do to the other too!
¨To convert slope intercept è standard form:
¶ Start by moving the mx to the opposite side of the equation,
to be with y. Simply subtract mx from both sides:
y = mx + b
-mx -mx
resulting in… -mx+y=b (same as … -Ax + y= C)
· Next you must get rid of the negative in front of the A (m).
Simply multiply all the numbers by (-) :
-Ax + y=C (same as… -mx+y=b)
-(-Ax+y=C) ê Ax-y=-C
¨ If your original slope (m) is a fraction:
¶ follow the steps above (move mx to opposite side and
get rid of negative if needed):
y= -mx+b ê mx+y=b
y= mx+b ê -mx+y=b ê mx-y=-b
· Now get rid of the fraction by multiplying each number
by the fraction’s denominator:
(3/4)x+y=2ê 4(3/4x+y=2) ê 3x+4y=8
¨ Now here are a couple of examples to help you out a little more.
Pay close attention to positive, negatives, and fractions:
h slope intercept: y= (1/2)x-7 ê
-(1/2)x+y=-7 ê
(1/2)x-y=7 ê
standard form: x-2y= 14
h slope intercept: y=-9x+3
standard form: 9x+y= 3
filling in your other wholes!!