Question

Выражение a) (x-3)(x-5)-2x(x-4) б) 4a(a-6)-(a-12)^2 в) (m+5)^2-10m

Answer 1

$a)(x - 3)(x - 5) - 2x(x - 4) = ( {x}^{2} - 5x - 3x + 15) - (2 {x}^{2} - 8x) = 15 - {x}^{2}$

$b)4a(a - 6) - (a - 12) {}^{2} = 4 {a}^{2} - 24a - ( {a}^{2} - 24a + 144) = 3 {a}^{2} + 144$

$c)(m + 5) {}^{2} - 10m = ( {m}^{2} + 10m + 25) = {m}^{2} + 25$

Answer 2

1.(x-3)(x-5)-2x(x-4)=

${x}^{2} - 5x - 3x + 15 - 2 {x}^{2} + 8x$

=

$- {x}^{2} + 15$

2.

${4a(a-6)-(a-12)}^{2}$

$4 {a}^{2} - 24a - {a}^{2} + 24a - 144$

$3 {a}^{2} - 144$

3.

$( {m + 5)}^{2} - 10m$

${m}^{2} + 10m + 25 - 10m$

${m}^{2} + 25$