Question

решите систему уравнений: х-у=4, у/2=х/5

Answer 1

$left { {{x-y=4} atop {0,5y=0,2x}} right. \x-2(0,5y)=4 \x-2(0,2x)=4 \x-0,4x=4 \0,6x=4 \x=frac{40}{6}=frac{20}{3}=6frac{2}{3} \y=2frac{2}{3}$

Answer 2

x-y=4

y/2 =x/5

5y=2x

x=5y/2

5y/2 - y = 4

5y - 2y = 8

3y =8

y=8/3

3x-8=12

3x=20

x=20/3