Exercise 4.1

1. Say, whether the Equation is Satisfied. (Yes/ No)

Instruction

Check whether the value given in the brackets is a solution to the given equation or not.

Instruction

Solve the following equations by trial and error method.

Instruction

Write equations for the following statements:

Instruction

Write the following equations in statement forms:

Instruction

Set up an equation in the following cases:

(i) Irfan says that he has 7 marbles more than five times the marbles Parmit has. Irfan has 37 marbles. (Take m to be the number of Parmit marbles.)

Solution:

Given: 7 more than five times Parmit marbles = Irfan's marbles = 37

Parmit's marbles = m

+ × m =

5m + 7 = 37

(ii) Laxmi’s father is 49 years old. He is 4 years older than three times Laxmi’s age. (Take Laxmi’s age to be y years.)

Solution:

Given: 4 years older than three times Laxmi's age = Laxmi's father age = 49

Laxmi's age = y

+ × y =

3y + 4 = 49

(iii) The teacher tells the class that the highest marks obtained by a student in her class is twice the lowest marks plus 7. The highest score is 87. (Take the lowest score to be l.)

Solution:

Given: twice the lowest marks plus 7 = Highest marks = 87

Let lowest marks be l. This gives us:

l + =

2l + 7 = 87

(iv) In an isosceles triangle, the vertex angle is twice either base angle. (Let the base angle be b in degrees. Remember that the sum of angles of a triangle is 180 degrees).

Solution:

Given: Iscocelese triangle

Vertex angle is twice either base angle.

Let base angle be 'b'.

So, baseangle1 = baseangle2 = b while vertexangle =

Sum of all angles = 180o

+ + 2 × = 180°

= °

4b = 180°