Question

Determinați numarul a din egalitatea: 315÷7+9-{4+[22-5×(204÷2-2×a)+16]÷4}=43

Answer 1

315:7+9-{4+[22-5*(204:2-2*a)+16]:4}=43
45+9-{4+[22-5*(102-2a)+16]:4}=43
54-[4+(22-510+10a+16):4]=43
4+(-488+10a+16):4=11
4+(-488+10a+16)=44
-488+10a+16=40
-488+10a=24
10a=-488+24
10a=-464 =>
=> a=-46,4 cm

Answer 2

(204:2-2xa)=(102-2a)
(102-2a) il notam cu b

315:7+9-{4+(22-5xb+16]:4]=43
45+9-[4+(22-5b+16)]:4=43
54-[4+(38-5b)]:4=43
(54-4+38-5b):4=43
(88-5b):4=43
88:4-5b:4=43
22-5b:4=43
5b:4=43+22
5b:4=65
5b=65x4
5b=260
b=260:5
b=52

dar b=102-2a=>102-2a=52
2a=102-52
2a=50
a=50:2
a=25