Question

已知函数f(x)=x的3次方-m+2,且f(5)=7,则f(-5)=

Answer 1

f(x)=x^3-m+2

f(5)=7

7 = 5^3-m+2

f(-5)=(-5)^3-m+2

7+f(-5)=[5^3+(-5)^3]-2m+4=[0]-2m+4=- 2m+4

f(-5)= - 2m-3

m=5^3-5=120

f(-5)= - 240-3= - 243