x+y=4x+y=4x+y=4
1x+1y=4\frac{1}{x}+\frac{1}{y}=4x1+y1=4
x+y=14x+y=\frac{1}{4}x+y=41
1x+1y=14\frac{1}{x}+\frac{1}{y}=\frac{1}{4}x1+y1=41