Question

answer these
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Answer 1

(4) (a) One variable

Explanation:

The given equation contain only one unknown value i.e. x, Apart x, all the values are constant. So, it is an equation in one variable.

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(5) (b) x = 11⠀⠀⠀⠀⠀⠀⠀⠀⠀

Explanation:

Solution of the equation means : for what value of the variable the equation will be true.

➞⠀$\sf 3x + 5 = 38$

➞⠀$\sf 3x = 38-5$

➞⠀$\sf 3x = 33$

➞⠀$\sf x = \dfrac{33}{3}$

➞⠀$\sf x = 11$

11 is the solution of the equation.

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(6) (c) 8⠀⠀⠀⠀⠀⠀⠀⠀⠀

Explanation:

Twice the sum of two numbers = 36

One number = 10

Let other number be x

According to the question:

➞⠀$\sf 2(x + 10) = 36$

➞⠀$\sf x + 10 = \dfrac{36}{2}$

➞⠀$\sf x + 10 = 18$

➞⠀$\sf x= 18-10$

➞⠀$\sf x = 8$

The other number is 8

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(7) (d) 15⠀⠀⠀⠀⠀⠀⠀⠀⠀

Explanation:

➞⠀$\sf \dfrac{1}{2} +\dfrac{b}{10} = 2$

L.C.M of 2 and 10 is 10

➞⠀$\sf \dfrac{5+b}{10} = 2$

➞⠀$\sf 5 +b = 2\times 10$

➞⠀$\sf 5+b = 20$

➞⠀$\sf b= 20-5$$\sf b = 15$

The value of b is 15

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(8) (d) x = 12⠀⠀⠀⠀⠀⠀⠀⠀⠀

Explanation:

➞⠀$\sf 5(x-3) = 45$

➞⠀$\sf x-3=\dfrac{45}{5}$

➞⠀$\sf x-3 = 9$

➞⠀$\sf x = 9+3$

➞⠀$\sf x = 12$

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(9) (c) 5⠀⠀⠀⠀⠀⠀⠀⠀⠀

Explanation:

Sum of 4 consecutive numbers is 26

• Let smallest number = x
• Second number = x + 1
• Third number = x + 2
• Fourth number = x + 3

According to the question:

➞⠀x + ( x + 1) + (x+2) +(x+3) = 26

➞⠀4x + 6 = 26

➞⠀4x = 26-6

➞⠀4x = 20

➞⠀x = 20/4

➞⠀x = 5

Smallest number = x = 5