Maths question - help please!

[Hollyhedge]

Am doing a course and need some maths and something is bugging me. What is the purpose of x in y = mx + c ? What does it represent and does it change? The equation is straightforward, but none of the explainers tell me this.

Wasn’t sure where to post - was at secondary around 30 years ago 🤪

Thank you!

y =mx + c is the equation of a line.

The equation tells you how y varies as x changes (or vice versa).

(x,y) are the coordinates of a point on the line.

Thanks - so why when you are working it out does x often stay as x? Practice questions require you to plug in m and c only. Is it just so you could plug in the x valué?

Appreciate your help - had block on this!

Straight line graphs - BBC Bitesize

This might help OP

It’s a rule for how to get your y coordinate from your x coordinate.

so y=2x+3 means double your x coordinate and add 3 to get y

so if your x coordinate is 3, your y coordinate would be 9

if you plot a whole load of x coordinates against their y coordinates the points form a straight line.

x represents any of the full range of values from minus infinity to infinity.
Think of drawing a line (any line) on a set of xy axes. There is an x value at any point you choose on the line.

At any specific point on the line x will have a fixed value. If you plug in a value for x, this will give you a fixed point on the line.

If you plug in different values for m and c the slope and position of the line will change. So you'll get different lines.

This makes a lot of sense. Everything I watched missed this. So you’re basically working out the relationship between x and y with the gradient and starting point (y intercept)? Thanks so much everyone

Got it!!! Thank you