Question

已知函数f(x)=3x的平方-5x+2,求f(-a),f(-根号2）,f(a+3),f(a)+f(3)的值?

Answer 1

f(-a)=3a^2+5a+2 f(-√2)=3x(-√2)^2-5(-√2)+2=6+5√2+2=8+5√2 f(a+3)=3x(a+3)^2-5(a+3)+2=3a^2+13a+14=(3a+7)(a+2) f(a)+f(3)=3a^2-5a+2+3x3^2-5x3+2=3a^2-5a+16