Question

IF x= 1, Y= 2 and Z=5, find the value i) 3x-2y+4z ii) x2+ y2+ z2 iii) 2x2- 3y2+z2 iv) xy+yz-zx v) 2x2y - 5yz+ xy2 vi) x3- y3-z3​

Answer 1

hope this is helpful to you

Answer 2

Answer:

i) 3x-2y+4z

=3 x 1 - 2 x 2 + 4 x 5

=3 - 4 + 20

=3 + 16

=19

ii) x2+ y2+ z2

=1 x 2 + 2 x 2 + 5 x 2

=2 + 4 + 10

=6 + 10

=16

iii) 2x2- 3y2+z2

= 2 x 2 - 3 x 2 x 2 + 5 x 2

=4 - 6 x 2 + 10

=4 - 12 + 10

=4 - 2

=2

iv) xy+yz-zx

=1 x 2 + 2 x 5 - 5 x 1

=2 + 10 - 5

=2 + 5

=7

v) 2x2y - 5yz+ xy2

=2 x 2 x 2 - 5 x 2 x 5 + 1 x 2 x 2

=8 - 10 x 5 + 4

=8 - 50 + 4

=8 - 46

= - 38

vi) x3- y3-z3

= 1 x 3 - 2 x 3 - 5 x 3

=3 - 6 - 15

=3 - 21

= - 18