左： ∑Fy=0 NA-4*3-5=0 ,(1)
∑MA=0 M-1.5(4*3)-3*5=0 ,(2)
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右 ：∑Fx=0 NAx-5(2/(2√5))=0 ,(1)
∑Fy=0 NAy+NB-5(4/(2√5))=0 ,(2)
∑MA=0 2.5+2NB+2.5*5(2/(2√5))-2*5(4/(2√5)) =0 ,(3)
*自己解方程吧
