1) 5(3-5a)² - 5(3а-7)(3а+7) = 5(9-30а+25а²) - 5(9а²-49) = 5(9-30а+25а²-9а²+49) = 5(16а²-30а+58)
2) (а+1)² + 3(а-1)² - 5(а+1)(а-1) = а²+2а+1+3(а²-2а+1) - 5(а²-1) = а²+2а+1+3а²-6а+3-5а²+5 = -а²-4а+9
3) (m-1)² - 4(m+1)² - 6(m+1)(m-1) = m²-2m+1 - 4(m²+2m+1) - 6(m²-1) = m²-2m+1m-4m²-8m-4-6m²+6 = -9m²-10m+3
4) 5(1-y)² - (3+у)² - 3(1-у)(1+у) = 5(1-2у+у²) - (9+6у+у²) - 3(1-у²) = 5-10у+5у²-9-6у-у²-3+3у² = 7у²-16у-7
5) 5(1+m)(1-m) - (2-m)² - 8(1-m)² = 5(1-m²) - (4-4m+m²) - 8(1-2m+m²) = 5-5m²-4+4m-m²-8+16m-8m² = -14m²+20m-7
По формулам сокращенного умножения
9b^2+12b+4 + 49 -9b^2-12b=
=53
чтд
1)56-9n=-5n
-8n+5n=-56
-3n=-56
n=-56:(-3)
n=56/3=18 2/18= 18 1/9
n=18 1/9
2)15x-8x=2-9x
15x-8x+9x=2
16x=2
x=16:2
x=8
3) 10z+7=9z+5
10z-9z=-7+5
z=-2
4)17-8y=4-7
-8y=4-7-17
-8y=-20
y=-20:(-8)
y= 20/8 = 2 4/8= 2 1/2= 2,5
5)10-11n=15-12n
-11n+12n=15-10
-n=5
n=-5
6)-9z+32=7z
-9z-7z=-32
-16z=-32
z=-32:(-16)
z=2
7)25-12m=45-8m
-12m+8m=-25+45
-4m=20
m=20:(-4)
m=-5
8)5y+15=4y+20
5y-4y=20-15
y=5