Question

X^2 - y^2 = 100

Answer 1

Answer:

20

Step-by-step explanation:

Let's start by rewriting the second equation in terms of "x":

$x+y=5$

Subtract y from both sides:

$x=5-y$

Now, substitute "5-y" for "x" in the first equation:

$(5-y)^2-y^2=100$

Note that:

$(a-b)^2=a^2-2ab+b^2$

$25-10y+y^2-y^2=100$

Cancel out like terms:

$25-10y=100$

Subtract 25 from both sides:

$-10y=75$

Divide both sides by -10

$y=\frac{75}{-10}=\frac{15}{-2}=-\frac{15}{2}$

Now, substitute this value back into either of the equations to solve for x.

$x+y=5\\x-\frac{15}{2}=5$

Add 15/2 to both sides:

$x=5+\frac{15}{2}\\x=\frac{10}{2}+\frac{15}{2}\\x=\frac{25}{2}$

Now, find the difference:

$x-y=\frac{25}{2}-(-\frac{15}{2})=\frac{25}{2}+\frac{15}{2}=\frac{40}{2}=20$