-1-4(-7+8х)=-2х-6
-1+28-32х=-2х-6
-32х+2х=-6+1-28
-30х=-33
х=1,1
5(5+3х)-10х=8
25+15х-10х=8
5х=8-25
5х=-17
х=-3,4
-6=-9(7+х)+4х
-6=-63-9х+4х
9х-4х=-63+6
5х=-57
х=-11,4
8х+4(7+8х)=4х+7
8х+28+32х=4х+7
8х+32х-4х=7-28
36х=-21
х=-7/12
{2x-3y=11
{4x+5y=-11
{x=(11+3y)/2
{4(11+3y)/2+5y=-11
(44+12y)/2+5y=-11
22+6y+5y=-11
11y=-11-22
11y=-33
y=-33/11 x=(11+3(-3))/2
y=-3 x=1
1) - 3х^2+4х-7=0 - корней нет
корней нет