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January 28, 2015

January 28, 2015

Posted by **Marian** on Tuesday, March 1, 2011 at 6:51am.

substitue x=7 into the equatiopn and explain why this shows that x=7 is the solution.

ok so i do this: if x=7 then the equation becomes

7^2-49=0

7^2=49

49-49=0

so x=7 is correct (is that explanation enough?)

now i have to write out a complete solution to the orginal equation - i thought i had already done that above, could someone help me out please!

- maths -
**Reiny**, Tuesday, March 1, 2011 at 8:56am**the solution:**

x^2 - 7x = 0

x(x-7) = 0

so x = 0 or x = 7

**the check:**

if x = 0

LS = 0^2 - 7(0) = 0

RS = 0

so x = 0

if x = 7

LS = 7^2 - 7(7) = 49-49 = 0

RS = 0

so x = 7

x = 0 or x = 7

(The correct way to verify a solution is to show for the given value that the original left side (LS) is equal to the original right side (RS) of the equation. )

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