ответ 27))) 27 разделить на 4 будет 6 остаток 3
1) (5y²-3y-1)-(8y²+2y-11)=5y²-3y-1-8y²-2y+11=
=-3y²-5y+10
2) (5y²-3y-1)+(8y²+2y-11)=5y²-3y-1+8y²+2y-11=
= 13y²-y-12
3) (3a+5b)-(9a-7b)+(-5a+11b)=3a+5b-9a+7b-5a+11b=
=-11a+23b
4) (3x²+2x)+(2x²-3x-4)-(-x²+19)=3x²+2x+2x²-3x-4+x²-19=
=6x²-x-23
5) 3p(8c+1)-8c(3p-5)=3p*8c+3p*1+(-8c)*3p+(-8c)*(-5)
24pc+3p-24cp+40c=24pc+3p-24cp+40c
3p+40=3p+40c
3p+40c-3p-40c=0
0=0
1) x² + 12x + 27 = 0
D = 12² - 4*27 = 144 - 108 = 36
X1,2 = (- 12 + - √36)/2 = (- 12 + - 6)/2
X1 = (- 12 + 6)/2 = - 3
X2 = (- 12 - 6)/2 = - 9
Ответ : - 3; - 9
2) 8x² - 13x - 6 = 0
D = 13² - 4*(-6)*8 = 169 + 192 =361
X1,2 = (13 + - √361)/16 = (13 + - 19)/16
X1 = (13 + 19)/16 = 32/16 = 2
X2 = (13 - 19)/16 = - 6/16 = - 0, 375
Ответ: - 0,375; 2