2x1+x3+x37-(x3+x5)+(x5+x7)-.+(x33+x35)-(x35+x37)
=2x1+x3+x37-8+12-16+20-24+28-32+36-40+44-48+52-56+60-64+68-72-(x3+x37)
=2x1+32-72
=2x1-40=(x1+x3)+(x37+x1)=2*2+2*38=80
∴2x1=120 => x1=60 报1的同学想的是60有解题过程吗设报“n”的同学想的是xn 2x1=(x1+x3)+(x37+x1)-(x3+x37) =2*2+2*38-(x3+x37) 【∵x2报的是“2”；x38报的是“38”】=80-[(x3+x5)-(x5+x7)+(x7+x9)_...+(x35+x37)]=80-(8-12+16-20+24-28+32-36+40-44+48-52+56-60+64-68+72)=80-40=40x1=20