A jigsaw to revise linear graphs and their equations. Do you remember y=mx+c? m is the gradient, c is the intercept on the y axis. If you have forgotten this look here first.

Some of these equations need re-arranging so you can find the gradient and intercept, but others are already in the y=mx+c format.

I think this is one of the best jokes yet! Do you get it?

Do you understand the difference between a formula, expression, identity and equation?

A formula is a rule written using symbols that describe a relationship between different quantities. Typical maths formulae include

A = πr² (area of a circle)

C=πd (circumference of a circle)

An expression is a group of mathematical symbols representing a number or quantity. Expressions never have equality or inequality signs like =, >, <, ≠ ,≥ ,≤. Some examples

3a

3xy + 4x

t² + t³

An identity is an equation that is always true, no matter what values are chosen.

Examples

3a + 2a =  5a

x²+x² = 2x²

5 x 10 = 10 x 5

An equation is a mathematical statement that shows that two expressions are equal. It always includes an equals sign.

Examples

x² =100

3x(x+5)= 42

(x+3)(x-2)=0

In the last exercise you learnt how to factorise quadratic expressions. We will now use this in order to solve simple quadratic equations.

Suppose x²+9x +20 = 0

If we factorise we get (x+4) (x+5) = 0

In other words, two numbers multiply together to make 0. This means one of those numbers must be 0!

So we know EITHER x+4 = 0 OR x+5 = 0

If x +4 = 0 x = -4

If x+5 =0 then x=-5

So the solution is x = -4 or -5

Remember quadratic equations will nearly always have 2 solutions.

Try this- you will probably need pencil and paper to factorise the equations first.

#### Simple equations

Can you solve the simple equations Test your knowledge on this science quiz to see how you do and compare your score to others. Quiz by mathswithgraham