Algebra
posted by Lexie .
Solve the quadratic equation.
3x^215x+18=0
I know that the formula to quadratic equation is x=b+and(square root)b^24ac divided by 2a.
I know that a=3, b=15 and c=18, then subsitute in and get two answers, my problem is that I keep getting an answer that does not work after I subsitute in the original equation. What do I do?

did you get
x = (15 ± √(225  4(3)(18) )/6 ?
= (15 ± √9)/6
= (15 ±3)/6
= 3 or 2
we could have divided the original equation by 3 to get
x^2  5x + 6 = 0
now it factors
(x3)(x2) = 0
so x = 3 or x = 2 
I got 3 and 2. But to check it, wouldn't you substitue it the 3 and then the 2 in the original equation and it should be 0=0?

and so it does
How did you get 2?
if you had a + and a  then you couldn't possible end up with +18 at the end.
if x= 3
3(9)  45 + 18 = ??
if x=2
3(42)  30 + 18 = ???
Respond to this Question
Similar Questions

algebra
Solve the quadratic equation: 2x(squared)+6x+12=0 I know you have to find two numbers that =24 (2 times 12) and have a sum of 6. But I can't think of any! Can someone please help? 
Algebra2
Find the polynomials roots to each of the following problems: #1) x^2+3x+1 #2) x^2+4x+3=0 #3) 2x^2+4x5 #3 is not an equation. Dod you omit "= 0" at the end? 
QUADRATIC EQUATION
r^2+8r=48 First bring the 48 to the other side of the equation r^2+8r48=0 Now you can use the quadratic formula. x=b+sqrt(b^2(4ac)) ¯¯¯¯¯¯¯2a¯¯¯¯¯¯¯¯¯ So... a=1 b=8 c=48 Now just plug the numbers into the quadratic … 
Math
Use the quadratic formula to solve each of the following quadratic equations... 1. 2x^25x=3 2. 3x^22x+1=0 Rearrange the equation in quadratic formula form. 2x^2 5x 3 = 0 Then use the formula. Tell me what you don't understand about … 
Pre Algebra
Please help me with some problems. Thank you! Solve the equation by square root property. 3. 2x^2 = 26 I don't understand how to solve this problem. Solve the equation using the quadratic formula. 7. 7x^2=8x 2 This is what I got … 
Algebra
Use the quadratic formula to solve the equation. Give exact answers: 2x^2 1 = 6x. The choices are: a) 3 + square root(7)/2, 3  square root(7)/2 b) 3 + square root(11)/2, 3  square root(11)/2 c) 3 + square root(7)/2, 3  square … 
Algebra
I was given this answers to a problems I solved but I do not understand what she means hope you can help. Before attempting to solve this quadratic equation, determine how many solutions there will be for this quadratic equation. Explain … 
Algebra
I was given this answers to a problems I solved but I do not understand what she means hope you can help. Before attempting to solve this quadratic equation, determine how many solutions there will be for this quadratic equation. Explain … 
Algebra
1. Parent Quadratic Equation 2. Coordinate of the vertex 3. quadratic formula A. b/2a B. y = 2x C.b^2  4ac D. y = a(x  h)^2 + k E. x = b +/ (square root of) b^2 4ac/2a I think the answers are: 1. B 2. C 3. E Are these correct? 
math help how do i do this
Decide which part of the quadratic formula tells you whether the quadratic equation can be solved by factoring. −b b^2 − 4ac 2a Use the part of the quadratic formula that you chose above and find its value, given the following …