What are the solutions to the equation x^2-21=4x ?

The solutions to the equation x^2-21=4x are x=7,x=-3

Find the zeros of x^2-21=4x

The zeros of x^2-21=4x are x=7,x=-3

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x^{2} - 21 = 4 x

x = 7, x = - 3

Solution steps

x^{2} - 21 = 4 x

Move

4 x

to the left side

x^{2} - 21 - 4 x = 0

Write in the standard form

a x^{2} + b x + c = 0

x^{2} - 4 x - 21 = 0

Solve with the quadratic formula

x_{1, 2} = \frac{- ( - 4 ) \pm ( - 4 ) ^{2} - 4 \cdot 1 \cdot ( - 21 )}{2 \cdot 1}

(- 4)^{2} - 4 \cdot 1 \cdot (- 21) = 10

x_{1, 2} = \frac{- ( - 4 ) \pm 10}{2 \cdot 1}

Separate the solutions

x_{1} = \frac{- ( - 4 ) + 10}{2 \cdot 1}, x_{2} = \frac{- ( - 4 ) - 10}{2 \cdot 1}

x = \frac{- ( - 4 ) + 10}{2 \cdot 1} : 7

x = \frac{- ( - 4 ) - 10}{2 \cdot 1} : - 3

The solutions to the quadratic equation are:

x = 7, x = - 3

3 x^{- 4} y^{9} \cdot 8 x^{- 1} y^{- 6}

12 8^{\frac{1}{4}} \cdot 2^{\frac{1}{4}}

- \frac{18}{3}

5 = 2 + 3

x^{2} + 17 x + 42

What are the solutions to the equation x^2-21=4x ?
The solutions to the equation x^2-21=4x are x=7,x=-3
Find the zeros of x^2-21=4x
The zeros of x^2-21=4x are x=7,x=-3