Homework Help: maths

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

x^2-7x = 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
7^2-49=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. )

Answer this Question

Related Questions

ALGEBRA - please help me explain this in 50 words.. Explain why the equation -6(...
ALGEBRA - Beagleboy how do I explain that in 50 words? Post your 50-word ...
ALGEBRA - Post your 50-word response to the following: Explain why the equation...
College Algebra - Problem: Use Common or Natural Logarithims to solve the ...
CountIblis, can i bother you - Countiblis, i know that you might be busy do you ...
math - I asked sue a question yesterday and don't understand the answer can ...
math-rational equations - how do I solve 5/x-3+3/x+3=7x/x^2-9 please explain in ...
Variable - SOLVING EQUATIONS WITH THE VARIABLE ON BOTH SIDES Solve the equation...
algebra - do I do this correct and if not can you please show and tell me what I...
Algebra - Add and subtract the rational expressions as indicated. Be sure to ...

For Further Reading

First Name:
School Subject:
Answer: