Solve 3x = 8 - 3x 7x

Evaluate

3 x = 8 - 3 x \times 7 x

Multiply

More Steps

3 x = 8 - 21 x^{2}

Swap the sides

8 - 21 x^{2} = 3 x

Move the expression to the left side

8 - 21 x^{2} - 3 x = 0

Rewrite in standard form

- 21 x^{2} - 3 x + 8 = 0

Multiply both sides

21 x^{2} + 3 x - 8 = 0

Substitute a= 21,b= 3 and c= - 8 into the quadratic formula x = \frac{- b \pm b ^{2} - 4 a c}{2 a}

x = \frac{- 3 \pm 3 ^{2} - 4 \times 21 ( - 8 )}{2 \times 21}

Simplify the expression

x = \frac{- 3 \pm 3 ^{2} - 4 \times 21 ( - 8 )}{42}

Simplify the expression

More Steps

x = \frac{- 3 \pm 681}{42}

Separate the equation into 2 possible cases

x = \frac{- 3 + 681}{42} x = \frac{- 3 - 681}{42}

Use \frac{- a}{b} = \frac{a}{- b} = - \frac{a}{b} to rewrite the fraction

x = \frac{- 3 + 681}{42} x = - \frac{3 + 681}{42}

Solution

x_{1} = - \frac{3 + 681}{42}, x_{2} = \frac{- 3 + 681}{42}

Alternative Form

x_{1} \approx - 0.692761, x_{2} \approx 0.549904

Solve the quadratic equation