Question

Помогите, пожалуйста. :с
1)Найдите значение выражения:
4(1+3х)^2-24х
3у(2х-5)-2х(у+1)

2)Найдите значение выражения:
(х^2-25)/(х^2-8х+15)
(n^2+2n+1)/(n^2+5n+4)
(х^3-1)/(2х^2+х-3)

3)Решите уравнение
5х^2-2х=0

Answer 1

1.
а)4(1+3х)^2-24х = 4(1^2+2*1*3х+(3х)^2)-24х = 4(1+6х+(3х)^2)-24х = 4(1+6х+9х^2)-24х = 4+24х+36х^2-24х = 4+0+36х^2 = 4+36х^2 = 36х^2+4
б)3у(2х-5)-2х(у+1) = 3у*2х-3у*5-2х*(у+1) = 6ху-15у-2х*(у+1) = 6ху-15у-2ху-2х = 4ху-15у-2х = 4ху-2х-15у
2.
а) (х^2-25)(х^2-8х+15) = (х+5)(х-5)х^2-8х+15 = (х+5)(х-5)х^2-3х-5х+15 = (х+5)(х-5)х(х-3)-5х+15 = (х+5)(х-5)х(х-3)-5(х-3) = (х+5)(х-5)(х-5)(х-3) = х+5х-3
б) (n^2+2n+1)/(n^2+5n+4) = (n+1)^2/n^2+5n+4 = (n+1)^2/n^2+4n+n+4 = (n+1)^2/n(n+4)+n+4 = (n+1)^2/n(n+4)+1(n+4) = (n+1)^2/(n+1)(n+4) = (n+2)^2-1/n+4 = (n+1)^1/n+4 = n+1/n+4
в)(х^3-1)/(2х^2+х-3) = (х-1)(х^2+х+1^2)/2х^2+х-3 = (х-1)(х^2+х+1)/2х^2+3х-2х-3 = (х-1)(х^2+х+1)/х(2х+3)-1(2х+3) = (х-1)(х^2+ъ+1)/(х-1)(2х+3) = х^2+х+1/2х+3
3.
5х^2-2х=0
{ х=0. {х=0. {х=0
5х-2=0. 5х=2. х= 2/5