Question

If x = 1, y = – 1, z = 3, a = 1, b = – 2, c = 2, find the value of
(a) ax² +by² - cz²
(b) x² + y² - 3xyz + a² (b - c)
(c) x² + y² + z² + 2ab +2bc +2ca + xyz​

Answer 1

Answer:

➥a² + b²+ c² = 25

➥(y – z)² + (z – x)² + (x – y)² = 25

➥y² + z² -2yz + z² + x² -2zx x² + y² -2xy = 25

➥2x² +2y² + 2z² - 2xy -2yz -2zx = 25

➥2(x² +y² + z² - xy - yz - zx) = 25

➥x² +y² + z² - xy - yz - zx = 25/2

➥x² +y² + z² - xy - yz - zx = 12.5 ..