Solve the equation by graphing. 3x^2 + 9x = 12
A. {-4, 1}
B. {-6, 2}
C. {-3, 4}
D. no real solution

Question

Solve the equation by graphing. 3x^2 + 9x = 12
	A.	{-4, 1}
	B.	{-6, 2}
	C.	{-3, 4}
	D.	no real solution

anonymous · Answer

subtract 12  from each side.

then just 

graph it. and look for the roots.

ranga · Answer

Subtract 12 from both sides.  Factor 3 out.  Graph it.

This is a quadratic equation.  It is a parabola.  Compare it to ax^2 + bx + c
and identify a, b and c. Since a is positive the parabola opens upward.  The x coordinate of the vertex is at -b/2a.  You can plug that x in and find the y coordinate of the vertex.  You can put in a few values of x such as 0,1,-1,2,-2, 3,-3, etc and get a few y values.  With all this information you should be able to draw the graph and determine the roots of the equation which is where the graph cuts the x axis