将两块含30°的直角三角板叠放成如右图那样,若OD⊥AB,CD交OA于E,则∠OED= _______°
已知单项式﹣ax+yb5与a3y﹣1bx+y是同类项,则x=______,y=______.
若单项式2a2bx﹣y与﹣3ax+yb4是同类项,则x=______,y=______.
若单项式x2yn与﹣2xmy3的和仍为单项式,则nm的值为______.
已知x6y2与﹣3x3myn﹣2是同类项,则5m﹣3n的值为______.
若a2bm和anb3是同类项,则m﹣n=______.