# Factorise means put into brackets Solve means Find the values of x which make the equation true.

## Presentation on theme: "Factorise means put into brackets Solve means Find the values of x which make the equation true."— Presentation transcript:

Factorise means put into brackets

Solve means Find the values of x which make the equation true

Factorise x 2 + 2x - 3 Because there is only one x 2, we are looking for: Two numbers which multiply together to give: -3 and Add together to give: +2

So x 2 + 2x – 3 = (x -1)(x +3) That is far as we go because we have only been asked to factorise it. We can not solve it because; we dont know what value it equals

What if the question said solve x 2 + 2x - 3 = 0 It is crucial that the equation equals ZERO Factorise as before x 2 + 2x – 3 = (x -1)(x +3) = 0 Because the brackets are multiplied, one of them must equal ZERO

So (x-1) = 0 or (x+3) = 0 So x = 1 or x = -3

A few for you to try.

Solve x 2 + 4x + 3 = 0 Firstly we must FACTORISE x 2 + 4x + 3 = (x+1)(x+3) = 0 Then we SOLVE IT x+1 = 0 or x+3 = 0 so x = -1 or x = -3

Solve x 2 + x – 2 = 0 FACTORISE x 2 + x – 2 = (x-1)(x+2) = 0 SOLVE (x-1) = 0 or (x+2) = 0 so x = 1 or x = -2

Solve x 2 - 3x + 2 = 0 (last one) Factorise x 2 - 3x + 2 = (x-1)(x-2) = 0 Solve x-1 = 0 or x-2 = 0 So x = 1 or x = 2

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