Posted by Marian on .
x^27x = 0
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
7^249=0
7^2=49
4949=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,
the solution:
x^2  7x = 0
x(x7) = 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) = 4949 = 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. )