a)7x-15=207x=20+15
7x=35
x=35;7
x=5
b)2(3x-7)+4=50
2(3x-7)=50-4
2(3x-7)=46
3x-7=46:2
3x-7=23
3x=23+7
3x=30
x=30;3
x=10
a)7x-3≤11
7x≤11+3
7x≤14
x≤14:7
x≤2
x∈{0,1,2,}
b)5-2x≥1
5-1≥2x
4≥2x
4:2≥x
2≥x
x∈{0,1,2}
3.15-7=8
x+x+8=46
2x=46-8
2x=38
x=38:2
x=19
eu am 18ani
fratele are 18+8=26ani