SOLUTION: z^2-4z=0

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Question 1118427: z^2-4z=0
Found 4 solutions by ankor@dixie-net.com, josgarithmetic, greenestamps, Alan3354:
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website!
z^2 - 4z = 0
add 4z to both sides
z^2 = 4z
divide both sides by z
z = 4
:
:
Check
z^2 - 4z = 0
z = 4
4^2 - 4(4) = 0
16 - 16 = 0

Answer by josgarithmetic(39617)   (Show Source):
You can put this solution on YOUR website!

Either or .

Answer by greenestamps(13198)   (Show Source):
You can put this solution on YOUR website!

There are 2 solutions, as shown in the second response you got.

In the solution from the first tutor, both sides of the equation were divided by the variable z. When solving an equation, avoid if at all possible dividing both sides of the equation by an expression involving variables that might have the value zero, because division by 0 is not valid.

In this problem, one of the solutions for the variable is zero; so the division by the variable is not valid, resulting in an answer which is missing one of the solutions.

Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website!
z = 0 and z = 4 are valid solutions.
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There is no division by zero.
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Check:
z^2-4z=0
z = 0
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0^2 - 4*0 = 0
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z^2-4z=0
z = 4
16 - 16 = 0