Question

15. Write 3.61492 x 10 in usual form.
16. Simplify the following expression and express the result in
(-4) + (-4)
17. Find the common factors of the given terms : 63mm, 54mn
18.Factorise (a - b)2 + 4ab
19. If 3125 is a multiple of 9, where z is a digit, what is the value
20. Can a polyhedron be formed with 18 faces, 10 vertices and 26​

Answer 1

Answer:

15.) 36.1492

16.) (-4)+(-4)

4-4 = -8

17.) 63mm, 54mn= 9, m.

18.) (a-b)²+ 4ab=

using identity (a-b)² =a²+b²- 2ab

= a²+b² -2ab +4ab

= a²+b²+2ab

using identity (a+b)² =a²+b²+2ab

=(a+b)²

19.) Given that 31z5 is a multiple of 9.

According to the divisibility rule of 9, the sum of all the digits should be a multiple of 9.

Therefore,

3+1+z+5=9 OR 18

⇒z=9−9=0

⇒z=18−9=9