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Jamus

Guest

how to verify algebra question

2y +30=8Y
8y-2y =6 y
6y +30
6y/6= 30/6
y=5
How to verify did I get it  right?

Jaspers

Member

Registered: 2019-05-24

Posts: 54

Re: how to verify algebra question

Hi Jamus.

You got the right answer but you need to write your steps more clearly.

To verify that it is the right answer, substitute y = 5 back in the original equation:

Last edited by Jaspers (2019-05-26 04:04:10)

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Reason is like an open secret that can become known to anyone at any time; it is the quiet space into which everyone can enter through his own thought.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,158

Re: how to verify algebra question

hi Jamus

Welcome to the forum.

The rules of algebra are just the rules for arithmetic so you always ought to be able to substitute numbers back to check the algebra.

Even when you don't have a number answer this can be useful.

example:  Suppose I have been asked to expand a bracket and I'm wondering if I've done it correctly.

Have I done this correctly?  Choose a value for x, say x = 5.

These two expressions have give the same result when x=5.  There is a small chance that my choice for x gave the same results by luck alone, but it's not likely.  To give myself a better chance of avoiding this I didn't choose x = 0, or x=1, or x = 3.

Recently I had some tricky algebra to simplify and I kept getting the wrong result.  So I started a spreadsheet and evaluated my expressions at each step.  As soon as I got a wrong number I knew I'd slipped up on that line of algebra and could find my error more easily. Ten lines later I had eliminated all my errors and I had the right result.  If you want to see why I was having difficulty here's the problem:

http://www.mathisfunforum.com/viewtopic.php?id=24996

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob