144q² - (3 - 12q)² = 144q² - 9 + 72q - 144q² = 72q - 9
48y + (3y - 8)² = 48y + 9y² - 48y + 64 = 9y² + 64
1) 7b -14 +2 - b = 6b -12 = 6 (b - 2)
2) 3x - 21 - 7y + xy = 3x +xy - 7y - 21
3) cx -5c +5 - x
4) x-p+pc-xc
Х-У=6 умножим все на -2
-2Х+2У=-12
+
5Х-2У=-3
=
3Х=-15
Х=-5
Х-У=6, У=Х-6, У=-5-6=-11