Question

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EXERCISE 60
Find each of the following products:
3. 8a? (2a +5b)
14 (3a +7b)
2. 5a (6a -3b)
4. 9x15x+7)
5. abla? -b)
6. 2x² (3x - 4x?
7. m nm 45m)
B. – 17x²13x - 4)
10 -4x² 4 13 x ² - 5y) 11. - 4 xyz ( 2 x²yz - 3 xyz² 12. gt² (t + 783)
13. 10a?.la -0.56) 14. 1.5a(10a²b-100ab%) 15. abcla? +62-30
16. Find the product 24x41--2x) and evaluate it for x = 2.
17. Find the product abla? + b) and evaluate it for a = 2 an
18. Find the product sís- st) and find its value for S = 2 and t = 3.
19. Find the product -3y xy + y) and find its value for x = 4 and y =5.
Simplify each of the following:
20. alb-c)+ble-a)+cla-b)
21 alb-c-ble-a-cla-b).
22. 3x + 2(x + 2)-3x (2x+1)
23. x(x + 4) + 3x (2x2 - 1) + 4x2 + 4
24. 2x2 + 3x (1-2x)+ x(x +1)
25. a'bla-b?) + ab 14ab-2a)-ab (1-2)
26. 4stts-t)-6sit-t?)-3t? (2s2 - S)+2st (s-t)​

Answer 1

Answer:

(i) Given 8a – 6ab + 5b, –6a – ab – 8b and –4a + 2ab+ 3b

= (8a – 6ab + 5b) + (–6a – ab – 8b) + (–4a + 2ab + 3b)

Collecting positive and negative like terms together, we get

= 8a – 6a – 4a –6ab – ab + 2ab + 5b – 8b + 3b

= 8a – 10a – 7ab+ 2ab + 8b – 8b

= –2a – 5ab

(ii) Given 5x3 + 7 + 6x - 5x2,

2x2 – 8 - 9x, 4x - 2x2 + 3 x 3, 3 x 3 - 9x - x2 and x - x2 - x3 – 4

= (5 x 3 + 7+ 6x - 5x2) + (2 x 2 – 8 - 9x) + (4x - 2x2+ 3 x 3) + (3 x 3 - 9x-x2) + (x - x2 - x3 - 4)

Collecting positive and negative like terms together, we get

5x3 +3x3 + 3x3 - x3 - 5x2 + 2x2- 2x2- x2 - x2 + 6x - 9x + 4x - 9x + x + 7 – 8- 4

= 10x3- 7x2 - 7x – 5