(i) ax² + bx
Answer: x(ax + b)
(ii) 7p² + 21q²
Answer: 7(p2 + 3q2)
(iii) 2x³ + 2xy² + 2xz²
Answer: 2x³ + 2xy² + 2xz²
= 2x(x²+y²+z²)
(iv) am² + bm² + bn² + an²
Answer: a(m2 + n2) + b(m2 + n2)
= (a + b)(m2 + n2)
(v) (lm + l) + m + 1
Answer: l(m + 1) + 1(m + 1)
= (l + 1)(m + 1)
(vi) y (y + z) + 9 (y + z)
Answer: (y + 9)(y + z)
(vii) 5y² – 20y – 8z + 2yz
Answer: 5y(y + 4) + 2z(y + 4)
= (5 + 2z)(y + 4)
(viii) 10ab + 4a + 5b + 2
Answer: 5b + 10ab + 2 + 4a
= 5b(1 + 2a) + 2(1 + 2a)
= (5b + 2)(1 + 2a)
(ix) 6xy – 4y + 6 – 9x
Answer: 6xy – 4y + – 9x + 6
= 2y (3x – 2) - 3 (3x - 2)
= (2y – 3)(3x – 2)
