Mohon bantu ya kawan smp kelas 3
2(3a)+(3a)=

2(3a) + (3a) = 9a

Remember the MDAS rule.
In an equation where multiple operations are present, always do these operations in order: Multiplication, Division, Addition, and Subtraction.

2(3a) + (3a) = 0
 6a + 3a = 9a

Do not be confused with the second (3a). It denotes multiplication where (3a) = 1(3a)

Maybe the answer is 20mm. all i really did was just multiply, which is obvious.