Answer:
The answer is (-3,7/2)
Step-by-step explanation:
[tex]2 {x}^{2} - x - 21 = 0 \\ (2x - 7)(x + 3) = 0 \\ 2x - 7 = 0 \: \: \: or \: \: x + 3 = 0 \\ x = \frac{7}{2} \: \: and \: x = - 3[/tex]
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