Number Properties Chapter 7 No. 9 ( Fourth Edition)

[afvatcha]

Hello,

My question is about no. 9, in chapter 7 of the Number Properties Guide.

My question is, when you clear out the X in the denominator, which X do you multiply it with? Is it the other X in the parenthesis, or the X outside the parenthesis? The other question is, what happens to the third X? The X in the denominator gets cancelled out. The second X is multiplied by the first X to give you X squared. What about the third X? In the answer it is like it doesn't exist.

X(X-(5x+6/x))=0

Thanks.

[tim]

there is no indication that the x inside the parentheses is multiplied by anything else in the parentheses. on the other hand, an x outside the parentheses means you are to multiply it by everything inside. to answer your second question, you have copied the question incorrectly. the (5x+6) should be in parentheses, as it is all over x. thus when we multiply by x the denominator goes away and the 5x-6 remains..

[manishdabas09]

Hi Tim,

I have a doubt about the same question.

Here it is mentioned x(x-5x+6/x)=0 and solution is x= 6 or -1. My question is why cant we have 0 as one more solution because in case x=0 then also LHS=RHS.

Thanks in advance.

Best Regards,
Manish

[messi10]

Hi Manish,

If you take x=0 as a solution, you don't get 0 on the LHS. You get infinity. Remember your Maths in school, a number divided by zero is undefined or infinite, NOT 0.

Regards

Sunil

[manishdabas09]

Many thanks for the reply Sunil ....

[messi10]

No problem at all

[jnelson0612]

Thanks Sunil!

[nabil.kayani]

can some one tell me how they did that problem step by step mathematically? I have read the solutions posted. I am still very confused. Thank you!

[tim]

Sorry, if there is already a solution out there that didn’t work for you, you’re not going to get anywhere by asking for a step by step solution because the solution that didn’t work for you IS a step by step solution. Instead, you need to tell us what you didn’t understand about the step by step solution you already read so we can help you with that..