Question

stiind ca a - 2b = 10 si 4b - 5c=85 sa se calculeze 4a - 10c

Answer 1

Valoarea expresiei .......................

Answer 2

a=2b+10;
4b=5c+85;
⇒2b=[5c+85]/2;
⇒a=[5c+85]/2+10⇒a=[5c+85+20]/2;
⇒4[5c+85+20]/2-10c
⇒2[5c+85+20]-10c
⇒10c+210-10c
⇒0+210=210;
⇒4a-10c=210;