Question

x-y=12 and xy=25÷4,findx+y​

Answer 1

Answer:

+13 or -13

Step-by-step explanation:

x-y = 12

then, x = 12+y

putting this value of x in xy = 25/4

we get, (12+y)y = 25/4

=> 12y+y^2 = 25/4

=> 4y^2 + 48y = 25

=> 4y^2 + 48y - 25 = 0 [ multiplying all by 4]

=> 4y^2 + 50y - 2y - 25 = 0

=> 2y (2y-1) +25 (2y-1) = 0

=> (2y-1) (2y+25) = 0

=> y = 1/2 or y = -25/2

for y =1/2

then x = 12+1/2 = 25/2

x+y = 25/2+1/2 = 26/2 === 13

or

for y = -25/2

then x = -1/2

So, x+y = -1/2 - 25/2 ===== -13