If the square of (x + y) is 7 and the square of (X-Y) is 5, find the value of XY Given the square of X - 2x = 2, find the square of (x-1) + (x + 3) (x-3) + (x-3) (x-1)

If the square of (x + y) is 7 and the square of (X-Y) is 5, find the value of XY Given the square of X - 2x = 2, find the square of (x-1) + (x + 3) (x-3) + (x-3) (x-1)

(x+y)²-(x-y)²=4xy
7-5=4xy
xy=1/2

5. Given X-Y = 7, xy = 60, find the value of x ^ 2 + y ^ 2 and (x + y) ^ 2

x-y=7 xy=60
x²+y²=(x-y)²+2xy=7²+2×60=49+120=169
(x+y)²=(x-y)²+4xy=7²+4×60=49+240=289

X * y = XY / x + y, find the value of 2 * (10 + 10)

1) What does x * y mean? If it is a special operation symbol, then x * y = XY / x + y = y + y = 2Y, then 2 * (10 + 10) = 2 * (10 + 10) = 482) if it is wrong, it should be x * y = XY / (x + y), then 2 * (10 + 10) = 2 (10 + 10) / [2 + (10 + 10)] = 40 / 22 = 20 / 113) if it is "multiply sign", then 2 * (10 + 10) = 40