Question

$8x { }^{2} - 22x \: - 21 = 0$

Answer 1

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$8 {x}^{2} - 22x - 21 = 0 \\ \\ or. \: \: 8 {x}^{2} - 28x + 6x - 21 = 0 \\ \\ or. \: \: 4x(2x - 7) + 3(2x - 7) = 0 \\ \\ or. \: \: (4x + 3)(2x - 7) = 0$
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Answer 2

$(i) \: Solution : \: \: \: \: \: We, \: have \: 8x {}^{2} - 22x - 21 = 0 \\ ⇒8x {}^{2} - 28x + 6x - 21 = 0 \\ ⇒4x(2x - 7) + 3(2x - 7) = 0 \\ ⇒(2x - 7)(4x + 3) = 0 \\ ⇒2x - 7 = 0 \: or \: 4x + 3 = 0 \\ ⇒x = \frac{7}{2} \: or \: x = \frac{ - 3}{4} \\ Thus, \: x = \frac{7}{2} \: and \: x = \: \frac{ - 3}{4} are \: two \: roots \: of \: given \: equation.$