Need Help
Given 21x^3-3x^2=0 , which values of x will satisfy the equation? (Hint: Factor the polynomial into two terms, and find the values of x that will make each term 0.)

A.
x = 0 and x = –7
B.
x = 0 and x = 7

C.
x=0 and x=-1/7

D. x=0 and x=1/7

Question

Need Help
Given 21x^3-3x^2=0 , which values of x will satisfy the equation? (Hint: Factor the polynomial into two terms, and find the values of x that will make each term 0.)

A.
x = 0 and x = –7
B.
x = 0 and x = 7
	
C. 
x=0 and x=-1/7

D. x=0 and x=1/7

zehanz · Answer

The two terms of this equation, $21x^3$ and $3x^2$, have common factors.
If you factor each term first, you can see all the common factors:

$21x^3=3\cdot7\cdot x \cdot x\cdot x$
$3x^2=3 \cdot x \cdot x$.

You can factor out the common factors (which are 3, x and x, obviously).

Now you have $3x^2(7x-1)=0$.

The equation now consists of two FACTORS and not terms btw.

So solve $3x^2=0$ and $7x-1=0$ to find the right answer...