Răspuns :
3x+7(a+b)=3*5+7*13=15+91=106
x(a+b)-50=5*13-50=65-50=15
10*5-4(a+b)=50-4*13=50-52=-2
(4(a+b)-2*5)(2(a+b)+5)= (4*13-10)(2*13+5)=
(52-10)(26+5)=42*31=1302
x(a+b)-50=5*13-50=65-50=15
10*5-4(a+b)=50-4*13=50-52=-2
(4(a+b)-2*5)(2(a+b)+5)= (4*13-10)(2*13+5)=
(52-10)(26+5)=42*31=1302