Question

Efectuati , folofind factorul comun : a) 7×13-7×3 b) 2008×2009-2006×2009-2×2007 c) 96×94-96×92-2×93 d) (5+17)×(31+27)+(5+17)×(19+23)

Answer 1

7x(13-3)=7x10=70


2009x(2008-2006)-2x2007=
=2009x2-2x2007
=2x(2009-2007)
=2x2=4


96x(94-92)-2x93=
=96x2-2x93
=2x(96-93)
=2x3
=6