1) (63x^2 + 49x - 81xy - 63y) - (-28x^2 - 56x - 8xy - 16y) = 63x^2 +49x -81xy - 63y + 28x^2 + 56x + 8xy + 16y) = 91x^2 + 105x - 72xy - 47y
2) (-70m^3 -90m)(5m - 8) = -350m^4 + 560m^3 -450m^2 + 720m
3) -2c(-9c - 2)(-7c - 9) = (18c^2 + 4c)(-7c - 9) = -126c^3 - 162c^2 - 28c^2 - 36c= -126c^3 - 190c^2 - 36c
4) (-7mn + 7m + 8n - 8) + (63mn + 49m - 81n - 63) = 56mn +56m - 72n - 71
5) (-25c^2 - 15c)(c + 7) = -25c^3 - 175c^2 -15c^2 - 105c = -25c^3 + 190c^2 - 105c = -25c^2 + 190c - 105
1. x^6 - 16
2. aby^2 + abx -cy^2 - cx
3. x^2 - y^4
4. 9m^4 - 4c^2
5. 36a^6 - 64b^2
6. 25n^8-m^8
3/7:к=5:7/3
3/7:к=5•3/7
3/7:к=15/7
К=3/7:15/7
К=3/7•7/15
К=3/15=1/5
К=1/5
А)x:14,4=4,8
x=4,8×14,4
x=69,12
б)x:8,02+4,7=11,2
x=11,2×8,02-4,7
x=85,124
в) 1,01×x-80,5=3,06
x=(3,06+80,5):1,01
x=82,7327