If 5x + 3y=4 and 5x-3y= 2, what is the value of (25x2 -9y2 )?

If 5x + 3y=4 and 5x-3y= 2, what is the value of (25x2 ${}^{\mathrm{<br>}}$ -9y2 ${}^{\mathrm{<br>}}$)?

Answer Details

5x + 3y=4

5x-3y= 2

Using elimination method 

5x + 3y=4 →    5x + 3y=4

-[5x-3y= 2] → -5x +3y= -2

6y = 2 

y → 1/3 and x = 3/5

solving (25x2 ${}^{\mathrm{<br>}}$ -9y2 ${}^{\mathrm{<br>}}$)

25 * [3/5]2 ${}^{\mathrm{<br>}}$ -9 * [1/3]2 ${}^{\mathrm{<br>}}$

25 * 925 $\frac{\mathrm{<br>}}{}$ - 9 19

9 - 1 = 8