Question

simplify the expression and evaluate

1) x(x-3)+2 for x=1
2) 3x(4x-5)+3 for x=1/2

Answer 1

Answer:

1)

$x(x - 3) + 2 \\ for \: x = 1 \\ {x }^{2} - 3x + 2 \\ = {1}^{2} - 3 \times 1+ 2 \\ 1 - 3 + 2 \\ = 3 - 3 \\ = 0$

2)

$3x(4x - 5) + 3 \: for \: x = \frac{1}{2} \\ 12 {x}^{2} - 15x + 3 \\ for \: x = \frac{1}{2} \\ 12 { (\frac{1}{2} })^{2} - 15 \times \frac{1}{2} + 3 \\ = 12 \times \frac{1}{4} - \frac{15}{2} + 3 \\ = 3 + 3 - \frac{15}{2} \\ = 6 - \frac{15}{2} \\ = \frac{12 - 15}{2} \\ = \frac{ - 3}{2}$