Question

2. If x=3.y =1 and z=-4 find the value of each of the following expressions.
(i) x2 + y2 +22 + 2xy + 2yz +2zx​

Answer 1

Step-by-step explanation:

Given x=−2,y=−1,z=3

x

2

+y

2

+z

2

−xy−yz−zx

=(−2)

2

+(−1)

2

+(3)

2

−(−2)(−1)−(−1)(3)−(3)(−2)

=4+1+9−2+3+6

=14−2+9

=12+9

=21