Question

Given y=x+4 and y=x^2 +4x, find x and y.

Answer 1

y=x+4 ...............(1)

`y=x^(2) +4x`...........(2)

plugging value of y from (1) in (2)

`x+4=x^(2) +4xx^(2) +4x-x-4=0x^(2) +3x-4=0factorising we get(x-1)(x+4) =0`

from here we get two values of x as

x-1=0, x=1 and x+4=0, x=-4

plugging x=1 in equation (1)

y=x+4 =1+4=5

plugging x=-4 in equation (1) , we get

y=x+4 =4-4 =0

so for x=1, y=5 and x=-4, y=0

Answer: x=1, y=5 and x=-4, y=5 points are (1,5) and (-4,5)