<p>If f(x)= 2x^2 +1, which of the following is a solution of the equation f(3x) = 3?</p>
<p>A) -3
B) -1/3
C) -1/9
D) 1/9
E) 3</p>
<p>the answer is B. why?</p>
<p>substitute it in.
x = -1/3,
f(3x) = f(-1) = 2*(-1)^2+1 = 2 + 1 =3, thus x = -1/3 is a soln </p>
<p>otherwise, solve for 3x.
f(3x) = 2*(3x)^2 + 1 = 18x^2 + 1 = 3
18x^2 = 2
x^2 = 1/9
x = -1/3 or 1/3</p>
<p>hey fiona 
haha</p>