Factorising quadratics, exercises 2

1: --[reporting2] Doing 'do snippet' - should be imbed--

Factorise y2 - 8y + 15

2: --[reporting2] Doing 'do snippet' - should be imbed--

Factorise s2 - 2s - 8

3: --[reporting2] Doing 'do snippet' - should be imbed--

Factorise z2 - 10z + 16

4: --[reporting2] Doing 'do snippet' - should be imbed--

Factorise 3b2 + 20b - 7

5: --[reporting2] Doing 'do snippet' - should be imbed--

Factorise 5x2 - x - 22