if X+y–z=4 and x²+y²+z²=30, then find value of xy–yz–zx.

Asked by pratimachouhan674 | 29th Jun, 2022, 11:53: AM

Expert Answer:

Given: x + y - z = 4
rightwards double arrow open parentheses straight x plus straight y minus straight z close parentheses squared equals 4 squared
rightwards double arrow straight x squared plus straight y squared plus straight z squared plus 2 xy minus 2 yz minus 2 zx equals 16
rightwards double arrow 30 plus 2 open parentheses xy minus yz minus zx close parentheses equals 16
rightwards double arrow 2 open parentheses xy minus yz minus zx close parentheses equals negative 14
rightwards double arrow xy minus yz minus zx equals negative 7

Answered by Renu Varma | 30th Jun, 2022, 12:00: PM