Question

ajutor dau coronita + 48 puncte. 2 si 3

Answer 1

Ex. 2:
a+b=27
b=a-7
a+a-7=27
a+a=27+7
a+a=34
2a=34
a=34:2
a=17
b=17-7
b=10


Ex.3:
a+b=345
a-b=255
a=255+b
255+b+b=345
2b=345-255
2b=90
b=90:2
b=45
a=255+45
a=300

Probă:300+45=345
300-45=255