Question

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

Answer 1

把值代入不就算出来了?f(负根号2)=3*2+5倍根号2+2=5+5倍根号2

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

f(a+3)=3(a+3)^2-5(a+3)+2=3a^2+13a-4

f(a)+f(3)=3a^2-5a+2+27-15+2=3a^2-5a+16