is that x a variable or multiplication symbol?
Step-by-step explanation:
if multiplication the answer is 12 • 10 to the 6th power or 12,000,000 they are the same
 
        
             
        
        
        
See56.7 cause it is the correct one to the 20th
        
             
        
        
        
3x + 34 
x = 4
Substitute x:
3 times 4 = 12
12 + 34 = 46
The answer is 46.
Hope this helped
        
                    
             
        
        
        
If you expand out the brackets you get this,
(4+5i)(a+2i) = 4a + (5a)i + 8i - 10
The -10 comes from 5i * 2i.
Squaring i becomes -1.
Let's group the real stuff together,
and imaginary separately,
(4a - 10) + (5a + 8)i
For this to be purely imaginary,
the real part needs to be zero.
Therefore 4a - 10 = 0
Solve for a.