What are the solutions to the equation x(21-x)=20 ?

The solutions to the equation x(21-x)=20 are x=1,x=20

Find the zeros of x(21-x)=20

The zeros of x(21-x)=20 are x=1,x=20

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x (21 - x) = 20

x = 1, x = 20

Solution steps

x (21 - x) = 20

Expand

x (21 - x) : 21 x - x^{2}

21 x - x^{2} = 20

Move

20

to the left side

21 x - x^{2} - 20 = 0

Write in the standard form

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

- x^{2} + 21 x - 20 = 0

Solve with the quadratic formula

x_{1, 2} = \frac{- 21 \pm 2 1 ^{2} - 4 ( - 1 ) ( - 20 )}{2 ( - 1 )}

2 1^{2} - 4 (- 1) (- 20) = 19

x_{1, 2} = \frac{- 21 \pm 19}{2 ( - 1 )}

Separate the solutions

x_{1} = \frac{- 21 + 19}{2 ( - 1 )}, x_{2} = \frac{- 21 - 19}{2 ( - 1 )}

x = \frac{- 21 + 19}{2 ( - 1 )} : 1

x = \frac{- 21 - 19}{2 ( - 1 )} : 20

The solutions to the quadratic equation are:

x = 1, x = 20

- 4 n^{2} = - 64

2 x^{2} + 12 x - 14

136 = 16 t^{2} + 100 t

23 y + 7 y^{2} = 20

2 - t - t^{2} = 0

What are the solutions to the equation x(21-x)=20 ?
The solutions to the equation x(21-x)=20 are x=1,x=20
Find the zeros of x(21-x)=20
The zeros of x(21-x)=20 are x=1,x=20