Ответ:

б) (x³-2x⁴+7)-(3x³+3-5x⁴) = 6+3x⁴

x³-2x⁴+7-3x³-3+5x⁴ = 6+3x⁴

x³-2x⁴-3x³+5x⁴-3x⁴ = 6-7+3

-2x³ = 2

x³ = -1

x = -1

в) 0,5y-(4.3y+2.7)+0.3y = 46.3

0.5y-4.3y-2.7+0.3y = 46.3

0.5y-4.3y+0.3y = 46.3+2.7

-3.5y = 49

y = -14

г) 1/3t + 2/5 + (3/5 + 2/3t) = 2 - 3t │*15

5t+6+9+10t = 30-45t

5t+10t+45t = 30-6-9

60t = 15

t = 0.25

д) -2.5x-(3.7-4.3x) = 1.7

-2.5x-3.7+4.3x = 1.7

1.8x = 5.4

x = 3

е) 2/5z = -(2/5 - z) + 3/5z + 8 │*5

2z = -2+z+3z+8

2z-z-3z = -2-8

-2z = -10

z = 5