Find out the value of x and y 3+x+xy=0 2x+5y=8 ???
Thanks in advance !
Thanks in advance !
1 Answer
Oct 12, 2017
Explanation:
3+x+xy=0to(1)
2x+5y=8to(2)
"rearrange equation "(2)" in terms of x or y"
rArrx=1/2(8-5y)=4-5/2yto(3)
"substitute "x=4-5/2y" in "(1)
rArr3+4-5/2y+4y-5/2y^2=0
rArr-5/2y^2+3/2y+7=0
"multiply through by "-2
rArr5y^2-3y-14=0
rArr5y^2-10y+7y-14=0larr" split middle term"
"factorise by grouping"
color(red)(5y)(y-2)color(red)(+7)(y-2)=0
"factor out "(y-2)
rArr(y-2)(5y+7)=0
"equate each factor to zero and solve for y"
y-2=0rArry=2
5y+7=0rArry=-7/5
"substitute these values into equation "(3)
"for corresponding values of x"
y=2tox=4-5=-1
y=-7/5tox=4+7/2=15/2
rArr"points of intersection "(-1,2)" and "(15/2,-7/5)
graph{(3+x+xy)(y+2/5x-8/5)((x+1)^2+(y-2)^2-0.04)((x-15/2)^2+(y+7/5)^2-0.04)=0 [-10, 10, -5, 5]}
