Question

25x2+64y2 - 80xy, when x = 4 and y = 2
find the answer​

Answer 1

Answer:

25×4²+64×2²

25×16+64×4

400+256

656

Answer 2

Answer:

16

Step-by-step explanation:

Let P = 25x²+64y²-80xy

=> P = (5x)² + (8y)² - 2(5)(8)xy

which forms the formula, (a-b)² = a² + b² + 2ab

=> P = (5x - 8y)²

Now given x=4 and y=2

=> P = {(5*4)-(8*2)}² = (20-16)² = 4² = 16