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