Question

What is the value of the expression when z=2z=2? 7z^2 -3z-10 7z 2 −3z−10

Answer 1

Answer:

Add the following:

(i) 3x and 7x

(ii) -5xy and 9xy

Solution:

We have

(i) 3x + 7x = (3 + 7) x = 10x

(ii) -5xy + 9xy = (-5 + 9)xy = 4xy

Question: 2

Simplify each of the following:

(i) 7x3y +9yx3

(ii) 12a2b + 3ba2

Solution:

Simplifying the given expressions, we have

(i) 7x3y + 9yx3 = (7 + 9)x3y = 16x3y

(ii) 12a2b + 3ba2 = (12 + 3)a2b =15a2b

Question: 3

Add the following:

(i) 7abc, -5abc, 9abc, -8abc

(ii) 2x2y, - 4x2y, 6x2y, -5x2y

Solution:

Adding the given terms, we have

(i) 7abc + (-5abc) + (9abc) + (-8abc)

= 7abc – 5abc + 9abc – 8abc

= (7 – 5 + 9 – 8)abc

= (16 – 13)abc

= 3abc

(ii) 2x2y +(-4x2y) + (6x2y) + (-5x2y)

= 2x2y - 4x2y + 6x2y - 5x2y

= (2- 4 + 6 - 5) x 2y

= (8 - 9) x 2y

=-x2y

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