Question

stiind ca a×b=3 supra 7 si a×c=15 supra 28, calculati a×(b+c)!!!

Answer 1

a*b=3/7
a*c=15/28
a*(b+c)=
=a*b+a*c=
=3/7+15/28=
=12/28+15/28=
=27/28

Answer 2

$a(b+c)=ab+ac=\frac{3}{7}+\frac{15}{28}=\frac{12+15}{28}=\frac{27}{28}$