Algebra - Factorisation - Cross method (monics).
Test Yourself 2.
Factorise each of the following expressions using the cross-method:
| Format | ||
| Both signs positive. | 1. z2 + 15z + 26
Answer.(z + 2)(z + 13). |
2. a2 + 13a + 36
Answer.(a + 4)(a + 9). |
| 3. s2 + 17st + 16t2
Answer.(s + t)(s + 16t). |
4. m2 + 14mn + 40n2
Answer.(m + 4n)(m + 10n). |
|
| Signs are negative then positive respectively. | 5. x2 - 5xy + 6y2
Answer.(x - 2y)(x - 3y). |
6. y2 - 11y + 24
Answer.(y - 3)(y - 8). |
| 7. f 2 - 15fg + 54g2
Answer.(f - 6g)(f - 9g). |
8. n2 - 17np2 + 60p4
Answer.(n - 5p)(n - 12p). |
|
| Signs are positive then negative respectively. | 9. x2 + 2x - 48
Answer.(x + 8)(x - 6). |
10. k2 + 3k - 88
Answer.(k + 11)(k - 8). |
| 11. d2 + 4df - 45f 2
Answer.(d + 9f)(d - 5f). |
12. g2 + 4gf 2 - 12f 4
Answer.(g + 6f2)(g - 2f2). |
|
| Signs are both negative. | 13. x2 - 6x - 27
Answer.(x + 3)(x - 9). |
14. w2 - 8w - 48
Answer.(w + 4)(w - 12). |
| 15. y2 - 8yz - 65z2
Answer.(y + 5z)(y - 13z). |
16. p4 - 3p2q2 - 10q4
Answer.(p2 + 2q2)(p2 - 5q2). |
|
| Randoms. | 17. a2 + 21a + 68
Answer.(a + 4)(a + 17). |
18. j2 - 16j - 80
Answer.(j + 4)(j - 20). |
| 19. r2 - 19rs + 90s2
Answer.(r - 9s)(r - 10s). |
20. f2 + 25fg - 150g2
Answer.(f + 30g)(f - 5g). |