解方程 我主要是求:格式!

“x∈{0,1,2,3,4,5,6,}”
x+6=10 13-x=7

x=10-6 x=13-7
x=4 x=6
x∈{0,1,2,3,4,5,6,} x∈{0,1,2,3,4,5,6,}
so方程解为x=4 so方程解为x=6

x(8-x)=15 3x+5=26

x^2-8x+15=0 3x=26-5
(x-3)(x-5)=0 3x=21
x=3 或 x=5 x=7
x∈{0,1,2,3,4,5,6,} x!∈{0,1,2,3,4,5,6,}
so方程解为x=3 或 x=5 so方程无解
晕啊,堂堂大学生解这种问题.