Walkthrough (factorise + cancel)

Simplify...

2

X + 2X - 15

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2

X + 4X - 23

(X-5)(X+3)

(X-7)(X+3)

X-5

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X-7s

1) factorise both equations using double brackets

(Or in exceptional cases, the quaudratic equation) factorise further until...

2) you have two sections the same. They cancel out, leaving you with the finished equation