Question

已知(a-5)的平方=a的平方-5的平方,求(15a的立方+5a的6次方)/(-5a的立方)的值

Answer 1

(a-5)²=a²-25

a²-10a+25=a²-25

-10a+25=-25

-10a=-50

a=5

(15a^3+5a^6)/(-5a^3)

=5a^3(3+a^3)/(-5a^3)

=-(3+a^3)

=-3-125

=-128