Question

a=4 supra 9
b+c=15 supra 18
c-d=9 supra 20
a*b+2*a*c-a*d=?
Va rog Spune-ți repede.

Answer 1

a=4/9
b+c=15/18=5/6
c-d=9/20
a×b+2×a×c-a×d=
=a(b+2c-d)=
=a(b+c+c-d)=
=4/9×(5/6+9/20)=
=4/9×(50+27)/60=
=4/9×77/60=
=77/135=
=0,5(703)