1. 5х³-4х+18+7х³+3х²-3 = 12х³+3х²-4х+15
5х³-4х+18-7х³-3х²+3 = -2х³-3х²-4х+21
2. 4х⁵-4х²; а²+8а-4а+32 = а²+4а+32
3. (х+18)/4 - (4х-3)/3 = 7
3(х+18) -4(4х-3) = 12*7
3х+54 -16х +12 = 84
-13 х = 84-54-12
-13х = 18
х = -18/13
4. (1/3 -9)(1/3+1) - (1/3 + 8)(1/3 +3) = -23 целых 25/27
а. 1/3-9 = (1-27)/9 = 26/9 г. 1/3+8 = (1+24)/3 = 25/3
б. 1/3+3 = (1+3)/3 = 4/3 д. 1/3+3 = (1+9)/3 = 10/3
в. 26*4/9*3 = 104/27 е. 25*10/3*3 = 250/9
ж. 104/27 - 250/9 = 104 -750/27 = - 646/27 =