已知函数f(x)=3x^2-5x+2,求f(-√2),f(-a),f(a-3),f(a)+f(3)的值

问题描述:

已知函数f(x)=3x^2-5x+2,求f(-√2),f(-a),f(a-3),f(a)+f(3)的值

f(a+3)=3(a+3)^2-5(a+3)+2
=3(a^2+6a+9)-5(a+3)+2
=3a^2+18a+27-5a-15+2
=3a^2+13a+14

f(-√2)=3(-√2)²-5(-√2)+2=6+5√2+2=8+5√2f(-a)=3(-a)²-5(-a)+2=3a²+5a+2f(a-3)=3(a-3)²-5(a-3)+2=3a²-23a+44f(a)+f(3)=3a²-5a+2+3*3²-5*3+2=3a²-5a+16