equations方程[式]equationn.相等；均衡；方程式；等式equations of mixed type混合型方程equation simplification[计] 方程简化equation of MDD and MID计算方程equation of correlation相关方程equation in one unknown一元方程equation of vane profile叶片型线方程equation in two unknowns二次方程式equations of equilibrium平衡方程equation of higher order高阶方程式,高阶方程equation for ideal gases理想气体方程