4m-4=4m
square both sides
(4m-4)^2=(4m)^2
16m^2-32m+16=16m^2
subtract 16m^2 from both sides
-32m+16=0
-32m=-16
m=1/2
2007-12-12 14:54:42 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
not sixty yet gave a clear explanation.... but here's my problem. In school, I was always taught that you could take the square root of both sides of an equation. Taking the square root is the same as raising something to the 1/2 power. Why is it ok to raise both sides to the 1/2 power but not ok to raise both sides to the 2nd power?
2007-12-12 15:06:17 · update #1
Hi! Any time you square both sides of an equation, you run the risk of introducing a new root that doesn't satisfy the original. Look at your original equation--subtract 4m from both sides and you obtain -4 = 0, so there is no solution.
Consider 2x = 6. The answer is x = 3. If you square both sides, you have 4x^2 = 36, x^2 = 9, and x = ± 3, which has a solution not included in the original problem. Oops!
Good luck!
2007-12-12 14:59:45 · answer #1 · answered by not sixty yet 2 · 1⤊ 0⤋
Squaring is one of those operations you can do to an equation that can create an equation with more solutions than the original equation. You can't trust that all the solutions you get in the end will work in what you started with. That's why you must go back and substitute your possible solution into the original equation and see if it works.
As was pointed out above already, you began with an equation that has no solutions at all.
2007-12-12 23:03:11 · answer #2 · answered by Steve H 5 · 0⤊ 0⤋
There is no way 4m - 4 can be equal to 4m.
First of all, 4m is already equal to itself. If you add or subtract something from it, even if you use different methods of solving for m, the equation will not be equal anymore.
Therefore, the equation has no solution or null.
2007-12-12 23:00:25 · answer #3 · answered by Anonymous · 0⤊ 0⤋
4m-4 can never = 4m because
4m-4 = 4m
subtract 4m from both sides an you have
-4 = 0 (not possible)
2007-12-12 22:59:07 · answer #4 · answered by MartinWeiss 6 · 0⤊ 0⤋
From the start...
4m-4 = 4m
4m-4 - 4m = 4m - 4m
-4 = 0
2007-12-12 22:57:36 · answer #5 · answered by disposable_hero_too 6 · 0⤊ 0⤋
its not possible one cuz 4m-4 does not equal to 4m
if you were to plug in ANY number, it work.
4(1) - 4 does not equal 4(1)
4(0.5) - 4 does not equal 4(.5)
unless your a god, its not possible.
2007-12-12 23:11:15 · answer #6 · answered by VatsuX 4 · 0⤊ 0⤋
Your work seems right, but I'm with the girl above me. And when you check your work, you get that -2 = 2. Hmm.. I really don't know.
2007-12-12 23:01:42 · answer #7 · answered by Cal Poly Chica 3 · 0⤊ 0⤋
What did you square it for?
The answer should be NO SOLUTION
2007-12-12 22:59:39 · answer #8 · answered by Anonymous · 0⤊ 0⤋
Your question is copied down wrong.
2007-12-12 23:00:07 · answer #9 · answered by Robert S 7 · 0⤊ 0⤋