Solve 369x^2+25x-6=0

$$369 { x }^{ 2 } +25x-6 = 0$$

Solve for x

$$x=\frac{\sqrt{9481}-25}{738}\approx 0.098062909$$

$$x=\frac{-\sqrt{9481}-25}{738}\approx -0.165813586$$

Steps Using the Quadratic Formula

All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.

$$369x^{2}+25x-6=0$$

This equation is in standard form: ax^{2}+bx+c=0. Substitute 369 for a, 25 for b, and -6 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{-25±\sqrt{25^{2}-4\times 369\left(-6\right)}}{2\times 369}$$

Square 25.

$$x=\frac{-25±\sqrt{625-4\times 369\left(-6\right)}}{2\times 369}$$

Multiply -4 times 369.

$$x=\frac{-25±\sqrt{625-1476\left(-6\right)}}{2\times 369}$$

Multiply -1476 times -6.

$$x=\frac{-25±\sqrt{625+8856}}{2\times 369}$$

Add 625 to 8856.

$$x=\frac{-25±\sqrt{9481}}{2\times 369}$$

Multiply 2 times 369.

$$x=\frac{-25±\sqrt{9481}}{738}$$

Now solve the equation x=\frac{-25±\sqrt{9481}}{738} when ± is plus. Add -25 to \sqrt{9481}.

$$x=\frac{\sqrt{9481}-25}{738}$$

Now solve the equation x=\frac{-25±\sqrt{9481}}{738} when ± is minus. Subtract \sqrt{9481} from -25.

$$x=\frac{-\sqrt{9481}-25}{738}$$

The equation is now solved.

$$x=\frac{\sqrt{9481}-25}{738} x=\frac{-\sqrt{9481}-25}{738}$$

Steps for Completing the Square

Quadratic equations such as this one can be solved by completing the square. In order to complete the square, the equation must first be in the form x^{2}+bx=c.

$$369x^{2}+25x-6=0$$

Add 6 to both sides of the equation.

$$369x^{2}+25x-6-\left(-6\right)=-\left(-6\right)$$

Subtracting -6 from itself leaves 0.

$$369x^{2}+25x=-\left(-6\right)$$

Subtract -6 from 0.

$$369x^{2}+25x=6$$

Divide both sides by 369.

$$\frac{369x^{2}+25x}{369}=\frac{6}{369}$$

Dividing by 369 undoes the multiplication by 369.

$$x^{2}+\frac{25}{369}x=\frac{6}{369}$$

Reduce the fraction \frac{6}{369} to lowest terms by extracting and canceling out 3.

$$x^{2}+\frac{25}{369}x=\frac{2}{123}$$

Divide \frac{25}{369}, the coefficient of the x term, by 2 to get \frac{25}{738}. Then add the square of \frac{25}{738} to both sides of the equation. This step makes the left hand side of the equation a perfect square.

$$x^{2}+\frac{25}{369}x+\left(\frac{25}{738}\right)^{2}=\frac{2}{123}+\left(\frac{25}{738}\right)^{2}$$

Square \frac{25}{738} by squaring both the numerator and the denominator of the fraction.

$$x^{2}+\frac{25}{369}x+\frac{625}{544644}=\frac{2}{123}+\frac{625}{544644}$$

Add \frac{2}{123} to \frac{625}{544644} by finding a common denominator and adding the numerators. Then reduce the fraction to lowest terms if possible.

$$x^{2}+\frac{25}{369}x+\frac{625}{544644}=\frac{9481}{544644}$$

Factor x^{2}+\frac{25}{369}x+\frac{625}{544644}. In general, when x^{2}+bx+c is a perfect square, it can always be factored as \left(x+\frac{b}{2}\right)^{2}.

$$\left(x+\frac{25}{738}\right)^{2}=\frac{9481}{544644}$$

Take the square root of both sides of the equation.

$$\sqrt{\left(x+\frac{25}{738}\right)^{2}}=\sqrt{\frac{9481}{544644}}$$

Simplify.

$$x+\frac{25}{738}=\frac{\sqrt{9481}}{738} x+\frac{25}{738}=-\frac{\sqrt{9481}}{738}$$

Subtract \frac{25}{738} from both sides of the equation.

$$x=\frac{\sqrt{9481}-25}{738} x=\frac{-\sqrt{9481}-25}{738}$$