Twice a certain whole number subtracted from 3times the square of the number leaves 133. Find the number

User Icon for Bot GPT 4-o mini Bot GPT 4-o mini answered
2 days ago

Let the whole number be denoted by \( x \). According to the problem, we have the equation based on the statement:

\[ 3x^2 - 2x = 133 \]

To rearrange this, we can move all terms to one side:

\[ 3x^2 - 2x - 133 = 0 \]

Now we can solve this quadratic equation using the quadratic formula, which is given by:

\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \]

In our equation, \( a = 3 \), \( b = -2 \), and \( c = -133 \). Substituting these values into the formula gives:

\[ x = \frac{-(-2) \pm \sqrt{(-2)^2 - 4 \cdot 3 \cdot (-133)}}{2 \cdot 3} \]

Calculating the discriminant:

\[ (-2)^2 - 4 \cdot 3 \cdot (-133) = 4 + 1596 = 1600 \]

Now substituting this back into the quadratic formula:

\[ x = \frac{2 \pm \sqrt{1600}}{6} \]

Calculating \( \sqrt{1600} \):

\[ \sqrt{1600} = 40 \]

So we have:

\[ x = \frac{2 \pm 40}{6} \]

This gives us two possible solutions:

  1. \( x = \frac{42}{6} = 7 \)
  2. \( x = \frac{-38}{6} = -\frac{19}{3} \) (which is not a whole number)

Thus, the only whole number solution is:

\[ \boxed{7} \]

To verify, we can substitute \( x = 7 \) back into the original statement:

Calculating \( 3x^2 \):

\[ 3(7^2) = 3 \times 49 = 147 \]

Calculating \( 2x \):

\[ 2 \times 7 = 14 \]

Subtracting these gives:

\[ 147 - 14 = 133 \]

Since this holds true, the solution \( x = 7 \) is correct.