We look for a pair of numbers that "add" to 7 and multiply to -8 and discover -1 and 8
4x^2+7x-2=
4x^2+(8x-x)-2=
4x^2+8x-x-2=
(4x^2+8x)-(x+2)=
4x(x+2)-1(x+2)
(4x-1)(x+2)
:)
4x^2+7x-2=
4x^2+(8x-x)-2=
4x^2+8x-x-2=
(4x^2+8x)-(x+2)=
4x(x+2)-1(x+2)
(4x-1)(x+2)
:)
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