Question 98587
x+x+2+x+4>10
3x+6>10
3x>10-6
3x>4
x>4/3 the first odd number>4/3=3 
proof
3+5+7>10
15>10
x+x+2+x+4<20
3x+6<20
3x<20-6
3x<14
x<14/3 the first odd number<14/3=3
proof
3+5+7<20
15<20
ultimate proof
1+3+5=8 not>10
5+7+9=21 not<20