The graphs of which functions approach positive infinity as x approaches both negative infinity and positive infinity? Selec all that apply. Select all that apply: f(x) = x+5x+9 f(x)=4x + 5x2 f(x)=19x4 +8x3 +1 f(x)=-9x5 + 4x4 +3x +8 f(x) = 18x5+8x +6 f(x)=3x+7x4 +9x