Question

设f(x)是x的一次函数,且2f(1)+3f(2)=3,2f(-1)-f(0)=-1,则f(x)等于?

Answer 1

设f(x)=kx+b

f(1)=k+b f(2)=2k+b f(-)=-k+b f(0)=b

所以, 2(k+b)+3(2k+b)=3 (1)

2(-k+b)-b=-1 (2)

解得: k=4/9 b=-(1/9)

所以, f(x)=4/9x-1/9