What are the solutions to the equation 3r^2+18r=21 ?

The solutions to the equation 3r^2+18r=21 are r=1,r=-7

Find the zeros of 3r^2+18r=21

The zeros of 3r^2+18r=21 are r=1,r=-7

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3 r^{2} + 18 r = 21

r = 1, r = - 7

Solution steps

3 r^{2} + 18 r = 21

Move

21

to the left side

3 r^{2} + 18 r - 21 = 0

Solve with the quadratic formula

r_{1, 2} = \frac{- 18 \pm 1 8 ^{2} - 4 \cdot 3 ( - 21 )}{2 \cdot 3}

1 8^{2} - 4 \cdot 3 (- 21) = 24

r_{1, 2} = \frac{- 18 \pm 24}{2 \cdot 3}

Separate the solutions

r_{1} = \frac{- 18 + 24}{2 \cdot 3}, r_{2} = \frac{- 18 - 24}{2 \cdot 3}

r = \frac{- 18 + 24}{2 \cdot 3} : 1

r = \frac{- 18 - 24}{2 \cdot 3} : - 7

The solutions to the quadratic equation are:

r = 1, r = - 7

\frac{10}{10}

\frac{3}{6} \cdot \frac{1}{6}

(\frac{a ^{3}}{2 b ^{5}})^{4}

\frac{6}{5} - (5 x - 3) = \frac{1}{5} x - 12

2 \cdot \frac{3}{2}

What are the solutions to the equation 3r^2+18r=21 ?
The solutions to the equation 3r^2+18r=21 are r=1,r=-7
Find the zeros of 3r^2+18r=21
The zeros of 3r^2+18r=21 are r=1,r=-7