How do you factor this 8x^2+2x-21=0

[tex]8x^2+2x-21=0 \\ \\ 8x^2+2x + 12x -12x-21=0\\\\8x^2+ 14x -12x-21=0 \\ \\ 2x(4x+7)-3(4x+7)=0\\\\(4x+7)(2x-3)=0[/tex][tex]4x+7=0 \ \ or \ \ 2x-3 =0 \\\\4x=-7\ \ or \ \ 2x=3\\\\x=\frac{-7}{4}\ \ or \ \ x=\frac{3}{2}[/tex]

Solve it like this.. 8x^2+2x-21=08x^2 + 14x - 12x -21=02x(4x+7) -3(4x+7) = 0(4x+7)(2x - 3)=0So factor 1 is 4x +7 =0 i.e. x=-7/4Factor 2 is 2x -3 =0i.e x=3/2