Equations

Equations:

Equations of a straight line:

An equation of a straight line can take on 2 forms.

The most common one is y=mx+c, where m is the gradient and c is the point it crosses the y axis.

For example, if we know the gradient is 3, and the line crosses the y axis at -2, then the formulae becomes y=3x-2

However, this formula can only be used when we know 2 points on a line. If we only know one, we can rearrange the formula to get y-b=m(x-a).

Here, we know the gradients and (a,b).

An example would be if we knew the gradient was 4 and the point was (-4,1)

The formula would then look like this: y-1=4(x+4) (The negatives cancel each other out.)

We can then solve this to get: y=9x.

Linear equations and Inequations:

A linear equation is an equation which may look like 2(9x-2) = 17+3x

We simply just need to solve the bracket and then rearrange the numbers.

This gets us 18x-4 = 17+3x

Which then becomes: 15x = 21

An inequation is only slightly different…