Solve the Cubic Equation: x³-7x²+6x=0 Using Factoring

Question

x37x2+6x=0 x^3-7x^2+6x=0

Video Solution

Solution Steps

00:05 Let's find the value of X.
00:08 First, factor out the term with X.
00:19 Next, take out the common factor from inside the parentheses.
00:34 Great job! This is one solution that makes the equation equal zero.
00:38 Now, let's check which solutions make the second term zero.
00:43 We'll factor using the trinomial. Let's identify the coefficients.
00:49 We need two numbers that add up to B, which is negative 7.
00:53 Plus, their product should equal C, which is positive 6.
00:58 Once we've found these numbers, we substitute them back in the parentheses.
01:02 Let's find the values that make each term zero.
01:07 And that's how we solve this problem. Well done!

Step-by-Step Solution

To solve the given cubic equation x37x2+6x=0 x^3 - 7x^2 + 6x = 0 , follow these steps:

  • Step 1: Identify that the equation can be factored by its Greatest Common Factor (GCF).

There is an x x common in all terms: x(x27x+6)=0 x(x^2 - 7x + 6) = 0

  • Step 2: Factor the quadratic expression x27x+6 x^2 - 7x + 6 .

Look for two numbers that multiply to 6 6 (the constant term) and add up to 7 -7 (the coefficient of the linear term). The numbers are 1 -1 and 6 -6 . Thus:

x27x+6=(x1)(x6) x^2 - 7x + 6 = (x - 1)(x - 6)

  • Step 3: Set each factor equal to zero to solve for x x .

Now that the equation is fully factored as x(x1)(x6)=0 x(x - 1)(x - 6) = 0 , apply the zero product property:

x=0 x = 0 , x1=0 x - 1 = 0 (so x=1 x = 1 ), x6=0 x - 6 = 0 (so x=6 x = 6 )

Thus, the solutions to the equation x37x2+6x=0 x^3 - 7x^2 + 6x = 0 are x=0 x = 0 , x=1 x = 1 , and x=6 x = 6 .

Answer

x=0,1,6 x=0,1,6