Question

daca se stie a+3b=5 si c=8 calculati 4a+12b+5c 

Answer 1

a+3b=5 /*4 inmultim relatia cu 4 si rezulta  4a+12b=20

c=8 =>5c=5*8=>5c=40

4a+12b+5c=20+40
4a+12b+5c=60

Answer 2

a+3b=5

c=8

4a+12b+5c=4*(a+3b)+12b+5*8=4*5+12b+40=20+12b+40=60+12b