Question

(a) Simplify 3x (4x −5) + 3 and find its values for (i) x = 3, (ii) .

(b) a (a² + a + 1) + 5 and find its values for (i) a = 0, (ii) a = 1, (iii) a = − 1.

Answer 1

(a) 3x (4x − 5) + 3 = 12x² − 15x + 3

(i) For x = 3, 12x² − 15x + 3 = 12 (3)² − 15(3) + 3

= 108 − 45 + 3

= 66

(ii) For

(b)a (a² + a + 1) + 5 = a³ + a² + a + 5

(i) For a = 0, a³ + a² + a + 5 = 0 + 0 + 0 + 5 = 5

(ii) For a = 1, a³ + a² + a + 5 = (1)³ + (1)² + 1 + 5

= 1 + 1 + 1 + 5 = 8

(iii) For a = −1, a³ + a² + a + 5 = (−1)³ + (−1)² + (−1) + 5

= − 1 + 1 − 1 + 5 = 4