Question

Q 8. If x = 1, y = 2 and z = 5, find the value of (i) 3x − 2y + 4z (ii) x 2 + y 2 + z 2 (iii) 2x 2 − 3y 2 + z 2 (iv) xy + yz − zx (v) 2x 2 y − 5yz + xy 2 (vi) x 3 − y 3 − z​

Answer 1

Answer:

Step-by-step explanation:

(i) substituting values we get,

3x1 - (2x2) + 4x5
 

= 3 - 4 + 20
= -1 + 20
= 19

(ii) substituting values we get,

1x2 + 2x2 + 5x2

= 2 + 4 + 10
= 6 + 10
= 16

(iii) substituting values we get,

2x1x2 - (3x2x2) + 5x2

= 4 - 12 + 10
= -8+10
= 2

(iv) substituting values we get,

1x2 + 5x5 - (5x1)

= 2 + 25 - 5
= 2 + 20
= 22

(v) substituting values we get ,

2x1x2x2 - (5x2x5) + 1x2x2

= 8 - 50 + 4
= -42+4
= -38

(vi) substituting values we get ,

(1x3) - (2x3) - 5

= 3 - 6 - 5
= -3 - 5
= -8

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