Х2-18х+80 / 5х-50 = х2-10х - 8x+80 / 5х-50 =
= x(х-10) - 8(x-10) / 5(х-10) =
= (х-10) (x - 8) / 5(х-10) =
= (x - 8) / 5
при х= -12 ; (-12 - 8) / 5 = - 4
при х= 48 ; ( 48 - 8) / 5 = 8
S7 = ?
b2=b1*q=1/2
b3=b1*q^2=1/4
q = 1/2
b1=1
S7 = b1*(q^7 - 1)/q-1
S7 = -127/128 /-1/2
S7 = 127/64
- 2a * 5b + 10aa⁶ - 7b³b² = - 10ab + 10a⁷ - 7b⁵ = 10a⁷ - 7b⁵ - 10ab
3a - 5b - 8a + 7b = 2b - 5a