Given that the rectangle is x²+4x-12, the possible sides will be given by:
a]
x²+4x-12
=x²+6x-2x-12
=x(x+6)-2(x+6)
=(x-2)(x+6)
thus the dimensions are (x-2) units (x+6) units
b]
x²+2xy-48y²
factorizing the above is:
x²+8xy-6xy-48y²
=x(x+8y)-6y(x+8y)
=(x+8y)(x-6y)
c]
24x²-4x-8
factoring the above we get:
=4(6x²-x-2)
=4(6x²+3x-4x-2)
=4(3x(x+2)-2(x+2))
=4(3x-2)(x+2)
=(12x-8)(4x+8)