What are the solutions to the equation r(r+2)=99 ?

The solutions to the equation r(r+2)=99 are r=9,r=-11

Find the zeros of r(r+2)=99

The zeros of r(r+2)=99 are r=9,r=-11

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r (r + 2) = 99

r = 9, r = - 11

Solution steps

r (r + 2) = 99

Expand

r (r + 2) : r^{2} + 2 r

r^{2} + 2 r = 99

Move

99

to the left side

r^{2} + 2 r - 99 = 0

Solve with the quadratic formula

r_{1, 2} = \frac{- 2 \pm 2 ^{2} - 4 \cdot 1 \cdot ( - 99 )}{2 \cdot 1}

2^{2} - 4 \cdot 1 \cdot (- 99) = 20

r_{1, 2} = \frac{- 2 \pm 20}{2 \cdot 1}

Separate the solutions

r_{1} = \frac{- 2 + 20}{2 \cdot 1}, r_{2} = \frac{- 2 - 20}{2 \cdot 1}

r = \frac{- 2 + 20}{2 \cdot 1} : 9

r = \frac{- 2 - 20}{2 \cdot 1} : - 11

The solutions to the quadratic equation are:

r = 9, r = - 11

x^{2} + 200 x + 10000 = 0

3 x^{2} + 12 x - 10 = - 3

\frac{1}{5} x^{2} + \frac{2}{5} x + 2 = 0

3 x^{(2)} + 13 = - 12 x

x^{2} + 12 x + 20 = 0

What are the solutions to the equation r(r+2)=99 ?
The solutions to the equation r(r+2)=99 are r=9,r=-11
Find the zeros of r(r+2)=99
The zeros of r(r+2)=99 are r=9,r=-11