Răspuns :
a)3(2a+3b)=87
2a+3b=87: 3=29
4a+6b=29*2=58
b)2(5a+6b)=30
5a+6b=15
15a+18b=15*3=45
2a+3b=87: 3=29
4a+6b=29*2=58
b)2(5a+6b)=30
5a+6b=15
15a+18b=15*3=45
6a+9b=87
3×(2a+3b)=87
2a+3b=87:3
2a+3b=29
4a+6b= 2×(2a+3b)=2×29=58
b) 10a+12b=30
2×( 5a+6b)=30
5a+6b=30:2
5a+6b=15
15a+18b= 3×(5a+6b)=3×15=45
3×(2a+3b)=87
2a+3b=87:3
2a+3b=29
4a+6b= 2×(2a+3b)=2×29=58
b) 10a+12b=30
2×( 5a+6b)=30
5a+6b=30:2
5a+6b=15
15a+18b= 3×(5a+6b)=3×15=45