Question

如图 直线AB过A (3m,0) B(0,n) m,n均大于0

Answer 1

1,

OA=3m,OB=n,

S△AOB=OA*OB/2=3mn/2;

2,

m+n=10

m=10-n,

S△AOB=3mn/2

=(3/2)[(10-n)n]

=(3/2)[-(n²-10n+25-25)]

=(3/2)[25-(n-5)²]

=(75/2)-(3/2)(n-5)²

(3/2)(n-5)²