Răspunsuri

2014-08-10T16:31:59+03:00
ABCD-ROMB
AC;DB-diag
AC intersectat DB={O}
DO=OB=DB/2
AO=OC=AC/2

ΔDOA, mas<O=90
AO=OD                            =>ΔDOA -dreptunghic isoscel =>

=>mas<A=mas<D=90/2=45 grade

<=> mas<DAC=45 grade

2)[(4x+1)-(2x+3)][(4x+1)+(2x+3)]=

=(4x+1-2x-3)(4x+1+2x+3)=

=(2x-2)(6x+4)=  2(x-1)(3x+2)