Question

4. If x + y = 10 and xy = 9, find the value of x - y.​

Answer 1

Answer:

X - Y = 8

Step-by-step explanation:

X = 9

Y = 1

Answer 2

Answer:

$(x + y) {}^{2} = {x}^{2} + {y}^{2} + 2xy \\ (10) {}^{2} = {x}^{2} + {y}^{2} + 2 \times 9 \\ 100 = {x}^{2} + {y}^{2} + 18 \\ 82 = x {}^{2} + y {}^{2}$

$(x - y {)}^{2} = x {}^{2} + y {}^{2} - 2xy \\ (x - y) {}^{2} = 82 - 2 \times 9 \\ (x - y) {}^{2} = 82 - 18 \\ (x - y) {}^{2} = 64 \\ x - y = \sqrt{64} \\ x - y = 8$