дана функция f(x)=x^3+3x-1 найдите f(-2) и f(x+1)

f(x) = x³ + 3x - 1

f(- 2) = (- 2)³ + 3 * (- 2) - 1 = - 8 - 6 - 1 = - 15

f(x + 1) = (x + 1)³ + 3(x + 1) - 1 = x³ + 3 * x² * 1 + 3 * x * 1² + 1³ + 3x + 3 - 1 =

= x³ + 3x² + 3x + 1 + 3x + 2 = x³ + 3x² + 6x + 3

f(-2)= (-2)³+3*(-2)-1= -8-6-1= -15

f(x+1)= (x+1)³+3*(x+1)-1= x³+3x²+3x+1+3x+3-1= x³+3x²+6x+3