how do you solve for the solution
x+9y=2(1)
x=9-y(2)

What level of math is this?

Its algebra in college

Haa crap once sec, I'll ask my boyfriend. Tutors Calculus ane linear Algebra. So he's a smarty pants.

Thank you because I'm stuck on that one and another one I posted if you could look at that one for me? Thanks

Quote:

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Originally Posted by AshleyRae09

thank you because im stuck on that one and another one i posted if you could look at that one for me? thanks

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Maybe copy and paste it?

solve with add and multiply 5+6x<53

When's it due? Monday? He might be taking his time. I had to text it to him.

Yeah its due Monday
Thankss

Here, the easiest way to solve it is by substitution.




The second equation shows you the 'value' of x. So, use that in the first equation.



Since 'x' is 9-y, replace the value of 'x' like this:



Did you see it? I replaced the x by its equal value, that is 9-y.

Now, it's easy to find y.





- y + 9y gives + 8y



Now remove 9 from both sides:



The 9 cancels out on the left hand side:





Divide both sides by 8:



The 8 cancel out on the left hand side:





Here is the value of y.

Now replace that value in the previous equation,

Quote:

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Originally Posted by AshleyRae09

5+6x<53

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This one now.



Remove 5 from both sides:





Divide both sides by 6:





Here it is! :)

If you were to divide or multiply by a negative number at any time, you will have to change the inequality sign. '>' becomes '<' and vice versa.

I'll give you an example:

Let's say

That's true right?

Ok, let's multiply that by -2:





Is -10 really smaller than -12? No. If you plot these on a number line, -10 is larger than -12. So, when you multiply or divide by a negative number, always invert the inequality sign.

I hope it helped! :)

If you have more problems, don't hesitate to ask. Next time though, post what you did and got wrong, so that we know where the problem is. :)

HAHAHA OH GOSH! WHY didn't I think of that. I must have been tired last night, I could have doen that easily. :)