View Full Version : absolute value on both sides of the equal sign
fiftrombone
07-16-2006, 05:16 PM
if you have like l ax+b l = l cx+d l do you jsut solve it like ax+b = cx+d then solve also for ax+b = -(cx+d)?
if you have like l ax+b l = l cx+d l do you jsut solve it like ax+b = cx+d then solve also for ax+b = -(cx+d)?
You got it!
fiftrombone
07-16-2006, 05:34 PM
thanks a lot.
fiftrombone
07-16-2006, 05:38 PM
wait. that didnt work when i tried to solve my problem. it is the same variable on both sides of the equation. and it is an absolute value on both sides. how do i solve for x?
jonboy
07-16-2006, 05:56 PM
So this is exactly what we are trying to solve for \L x:
\L \left| {ax + b} \right| = \left| {cx + d} \right|
skeeter
07-16-2006, 05:58 PM
|ax + b| = |cx + d|
case 1 ...
ax + b = cx + d
ax - cx = d - b
x(a - c) = d - b
x = (d - b)/(a - c)
case 2 ...
ax + b = -(cx + d)
ax + b = -cx - d
ax + cx = -b - d
x(a + c) = -(b + d)
x = -(b + d)/(a + c)
fiftrombone
07-16-2006, 06:08 PM
ok thank you. i think when i worked my problem through the first time i just dod some math wrong becasue it does work. thank all so much for your help.
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