Question

Find and correct the errors in the following mathematical statement. Substituting x = −3 in (a) x^2 + 5x + 4 gives (−3)^2 + 5 (−3) + 4 = 9 + 2 + 4 = 15 (b) x^2 − 5x + 4 gives (−3)^2 − 5 (−3) + 4 = 9 − 15 + 4 = −2 (c) x^2 + 5x gives (−3)^2 + 5 (−3) = −9 − 15 = −24

Answer 1

Correction:


$a) {x}^{2} + 5x + 4$
$put \: \: \: x = - 3 \\ \\ = ( { - 3)}^{2} + 5( - 3) + 4 \\ \\ = 9 - 15 + 4 \\ \\ = 13 - 15 \\ \\ = - 2$
$b) \: \: {x}^{2} - 5x + 4 \\ \\ = >\: {( - 3)}^{2} - 5( - 3) + 4 \\ \\ = 9 + 15 + 4 \\ \\ = 28$
$c) \: \: {x}^{2} + 5x \\ \\ = ( { - 3)}^{2} + 5( - 3) \\ \\ = 9 - 15 \\ \\ = - 6$
Hope it helps you