【单选题】
由理想集成运放组成的运算电路如图所示,其输出电压表达式为()。<br /> <img src="https://nimg.ppkao.com/2017-12/xieqiushi/2017120716321297696.jpg?sign=17db120a36d5f22933964e914f3b8916&t=62d1cb9e" /><br /> <img src="https://nimg.ppkao.com/2017-12/xieqiushi/2017120716322022704.jpg?sign=980b924503732992d2200e08d9aa81c6&t=62d1cb9e" />
A、A
B、B
C、C
D、D