根据题意可得方程:
15(a^2-3)-15a=2×5(a^2-3)-5a
15a^2-45-15a=10a^2-30-5a
15a^2-15a-10a^2+5a-45+30=0
5a^2-10a-15=0
a^2-2a-3=0
(a+1)(a-3)=0
a1=-1(舍去),a2=3
答:a=3
根据题意可得方程:
15(a^2-3)-15a=2×5(a^2-3)-5a
15a^2-45-15a=10a^2-30-5a
15a^2-15a-10a^2+5a-45+30=0
5a^2-10a-15=0
a^2-2a-3=0
(a+1)(a-3)=0
a1=-1(舍去),a2=3
答:a=3