[Mattlock]

I don't understand how to do this kind of stuff... here is one of my problems:
8y - 3 = 15 + 2y. Thank you for your help everyone... if you get to this in time for me to finish it.

[CRockGuitarist]

Originally Posted by skilletswitch

I don't understand how to do this kind of stuff... here is one of my problems:
8y - 3 = 15 + 2y. Thank you for your help everyone... if you get to this in time for me to finish it.

I assume you are solving for y...
8y - 3 = 15 + 2y
(8y - 3) - 2y = (15 + 2y) - 2y
6y - 3 = 15
(6y - 3) + 3 = 15 + 3
6y = 18
(6y)/6 = 18/6
y = 3

there you go

[JaytheK]

Well, I shall try to explain the best I can. First, you start with your equation: 8y - 3 = 15 + 2y. One of the rules of equations is something like this: equal values can be added to both sides of an equation without changing the validity of the equation.

Example: 2 = 2
2 + 3 = 2 + 3
5 = 5

The equation is still true, just the values have changed. But the values aren't the main idea of an equation. The main focus of an equation is whether the equation is true or false. So solving your equation would go something like this.

Starting equation: 8y - 3 = 15 + 2y
Subtract 2y from both sides: 8y - 3 - 2y = 15 + 2y - 2y
Giving you: 6y - 3 = 15
Add 3 to both sides: 6y - 3 + 3 = 15 + 3
Giving you: 6y = 18

Stop right here. Another rule of equations goes something like this: the same non-zero value can be multiplied or divided by every term in the equation. So we start where we left off.

Equation: 6y = 18
Divide every term by 6 (in this case, the only terms are 6y and 18): 6y/6 = 18/6
Giving you: y = 3

'hope that helps!

In Christ,
John

[jbm222]

I would just subract the entire left side from both sides yeilding:
6y-18=0

then add 18 to both sides

6y = 18

divide by 6

y=3

I guess it's about the same number of steps in the long run, but it's a lot faster in my head that way, and this method might be necessary with polynomials of a degree greater than 1.