a乘(2a一l)等于3a乘a等于几肿么算

首先，我们来解方程a(2a-1)=3a^2。
根据乘法原理，我们可以得出：
a * (2a - 1) = a * 3a
合并同类项后得到：
3a^2 - a = 3a^2
移项化简得到：
- a = 0
所以，当a等于0时，方程a(2a-1)=3a^2有解。
接下来我们来解方程a^2+a=0。
根据配方法或者因式分解法都可以解此二次方程：
a^2 + a = 0
a^2 + 2a + 1 = 1 + 1
(a + 1)^2 = 2
Taking the square root on both sides gives:
|a + 1| = sqrt(2)
So, we get two possible solutions:
a + 1 = sqrt(2) (or)
-a -1 = -sqrt(2)
Simplifying these expressions gives:
a = -1 + sqrt(2) (or) a = -1 - sqrt(2)
So when a equals -1 + sqrt(2) or -1 - sqrt(2), the equation a^2 + a = 0 has no solution.
最后，我们来解方程a(a+1)=0。
根据二次方程的性质，我们可以得出：
a * (a + 1) = 0
Since we know that for a variable to be zero, it must be equal to zero or a number that multiplied with it gives zero (such as -1). Therefore:
a = 0 or a + 1 = 0
Simplifying these expressions gives:
a = 0 or a=-1
So when a equals zero or -1, the equation a(a+1)=0 has no solution.
综上所述，在这个数学问题中，当a等于0时，方程a(2a-1)=3a^2有解。而方程a^2+a=0和方程a(a+1)=0都无解。