11х-(7+3х-2х²) = 2х²-2х-15
11х-7-3х+2х² = 2х²-2х-15
11х-7-3х+2х²-2х²+2х+15 = 0
10х+8 = 0
10х = -8
х = -0,8
11х-(7+3х-2х²) = 2х²-2х-15
11х-7-3х+2х² = 2х²-2х-15
11х-7-3х+2х²-2х²+2х+15 = 0
10х+8 = 0
10х = -8
х = -0,8