Question

If x+y=13 and xy is 25/4 find x-y

Answer 1

Answer:

x+y =13

xy =25/4

x-y = √[(x+y)^2 -4xy]

=√[(13)^2 -4(25/4)]

=√(169-25)

= √144

=12

hence x-y =12

#answerwithquality #BAL

Answer 2

Answer:

The value of x-y=-12

Step-by-step explanation:

Given : x+y=13 and xy=\frac{25}{4}

To find : The value of x-y ?

Solution :

Let x+y=13 ......(1)

xy=\frac{25}{4} ......(2)

Substitute the value of x from (1) and put in (2),

(13-y)y=\frac{25}{4}

13y-y^2=\frac{25}{4}

y^2-13y+\frac{25}{4}=0

4y^2-52y+25=0

(y-0.5)(y-12.5)=0

y=0.5,12.5

Substitute in (1),

When y=0.5, x+0.5=13

x=13-0.5=12.5

When y=12.5, x+12.5=13

x=13-12.5=0.5

Therefore, The values are (0.5,12.5) and (12.5,0.5).

Now, Substitute in x-y

When, x=0.5 and y=12.5

x-y=0.5-12.5=-12

When, x=12.5 and y=0.5

x-y=12.5-0.5=-12