Find and correct the errors in the following mathematical statements:
Substituting x = - 3 in
(a) x2 + 5x + 4 gives (-3)2 + 5 ( - 3) + 4 = 9 + 2 + 4 = 15
(b) x2 – 5x + 4 gives (-3)2 – 5 (- 3) + 4 = 9 – 15 + 4 = - 2
(c) x2 + 5x gives (-3)2 + 6( -3) = - 9 – 15 = - 24
