View Compilation Error

0_0_34652925_25158.cpp: In function 'int main()':
0_0_34652925_25158.cpp:18:11: error: expected primary-expression before '=' token
    temp + = log10((a-1+i)*1.0)-log10(1.0*i);  
           ^
0_0_34652925_25158.cpp:19:20: error: expected primary-expression before '=' token
             ans  + = pow(10.0,temp+(a+i)*log10(0.5));
                    ^