View Compilation Error

0_0_21586656_25367.cpp: In function 'int main()':
0_0_21586656_25367.cpp:17:20: error: expected primary-expression before '=' token
             temp + = log10((a-1+i)*1.0)-log10(1.0*i);    
                    ^
0_0_21586656_25367.cpp:18:20: error: expected primary-expression before '=' token
             ans  + = pow(10.0,temp+(a+i)*log10(0.5));  
                    ^