х+у=48 х*у=15 х=? у=?

Question

х+у=48

х*у=15

х=?

у=?

Answer 1

х+у=48

ху=15

 

x=48-y

xy=15

 

(48-y)y=15

48y-y²=15

y²-48y+15=0

Δ=(-48)²-4*1*15

Δ=2304-60

Δ=2244

√Δ=2√561

 

y₁=(-(-48)-2√561)/(2*1)

y₁=(48-2√561)/2

y₁=24-√561

 

y₂=(-(-48)+2√561)/(2*1)

y₂=(48+2√561)/2

y₂=24+√561

 

x₁=48-(24-√561)

x₁=48-24+√561

x₁=24+√561

 

x₂=48-(24+√561)

x₂=48-24-√561

x₂=24-√561

 

24+√561 и 24-√561