x=2
ax^5+bx^3+cx+7
=2^5a+2^3b+2c+7
=10
2^5a+2^3b+2c=10-7=3
x=－2
ax^5+bx^3+cx+7
=-2^5a-2^3b-2c+7
=-(2^5a+2^3b+2c)+7
=-3+7
=4