how do you...?

Question

how do you use variables...? fastest and most explained answer gets 10 points

Answer 1

Variables are used to represent numbers that you don't know. When you were in primary school you used boxes to represent unknown number. They were simple question but you used variables.

_ + 4 = 6, in the space would be a box and you would have to put a 2 in the box.
OK, now that you are older you use X's and Y's or what ever letter instead of boxes.

X + 4 = 6 We know it is 2 but how can you figure it out??
X = 6 - 4 I move the 4 from the left side to the right side.
X = 2
When you move a number from one side of your equation to the other side you MUST change the sign - that is why when I moved the 4 from the left side to the right side the + 4 became a - 4

2Y = 18 [2Y means 2 x Y (2 times Y)]
so when I move the 2 over to the right I must change the sign from times to divide
2Y = 18
Y = 18 / 2
Y = 9

When you have variable you want to put your variables on one side (usually the left side) and all your numbers on the other side (usually the right)

3X - 5 = 22
3X = 22 + 5
3X = 27
X = 27 / 3
X = 9

I hope this helps a bit. Move each number, one at a time, step by step.

Answer 2

You use variables to represent unknown quantities that, nonetheless, possess a certain mathematical relationship. For example, M=14h if the money you earn, M, is represented by the hours you work, h, multiplied by the amount that you make per hour, 14.