Question

Daca a+b=3,2 si b+c=5,3, calculati:
a)4a+5b+c
b)2a+7b+5c
c)3a+10b+7c
d)10a+12b+2c

Answer 1

a) 4a+5b+c=4×(a+b)+b+c=4×3.2+5.3=12.8+5.3 =18.1
b) 2a+7b+5c=2×(a+b)+5×(b+c)=2×3.2+5×5.3 =6.4+26.5=32.9
c) 3a+10b+7c=3×(a+b)+7×(b+c)=3×3.2+7×5.3
=9.6+37.1=46.7
d) 10a+12b+2c=10×(a+b)+2×(b+c)=10×3.2+2×5.3 =32+10.6=42.6