Q16 of 38 Page 10

Let’s solve:

i.


ii.


iii.


iv.


v.


vi.


i. 6x = 72


Dividing both side by 6, we get


x = 12


ii. 9x + 2 = 20


⇒ 9x + 2 – 2 = 20 – 2


⇒ 9x = 18


Dividing both side by 9, we get


⇒ x = 2


iii. 4x – 2x + 3 = 9 – 4x


Simplifying, we get


2x + 3 = 9 – 4x


⇒ 2x + 4x = 9 – 3


⇒ 6x = 6


Dividing both side by 6, we get


⇒ x = 1


iv.


Taking LCM, we get



Cross Multiplying, we get


⇒ -6x = 4(21 – 2x)


⇒ -6x = 82 – 8x


⇒ 8x – 6x = 82


⇒ 2x = 82


Dividing both side by 2


⇒ x = 41


v. 2x – 5{7 – (x – 6) + 3x} – 28 = 39


⇒ 2x – 5(7 – x + 6 + 3x) – 28 = 39


⇒ 2x – 5(13 + 2x) – 28 = 39


⇒ 2x – 65 – 10x – 28 = 39


⇒ 2x – 10x = 39 + 28 + 65


⇒ -8x = 132


Dividing both side by -8, we get



vi.


Taking LCM,



⇒


Cross-Multiplying we get,


⇒ 5(7x + 1) = 12(x + 79)


⇒ 35x + 5 = 12x + 948


⇒ 35x – 12x = 948 – 5


⇒ 23x = 943


Dividing both side by 23, we get


⇒ x = 41


More from this chapter

All 38 →
14

Let’s express following the expressions as sum of two squares:

i.


ii.


iii.


15

i. Let’s write for which value of t, will be a whole square form.

ii. Let’s write the expression which when added to gives a whole square.


iii. If a and b are positive integers and lets write the value of a & b.


iv. an identity or an equation? Write with reason.


v. For each positive or negative value of x and y except zero the value of is always (positive or negative)


 1

i. Through activity, folding a square sheet of paper construct angles of 45o, 90o.

ii. Let’s draw a parallelogram, cutting the paper and folding the angles let’s see how the diagonals intersect with each other.


iii. Folding the paper, let’s verify the properties of diagonals, square, rectangle and rhombus.


iv. Let’s construct a rhombus by 4 setsquares.


v. Let’s draw 45o, 90o the angles of 30o, 45o, 60o, 90o, 105o and 120o using set square.


2

Let’s draw 90o, 45o, 60o, 30o, 120o, 75o, 105o, 135o, 150o by scale and pencil compass.