Page 124 - Start Up Mathematics_7

Fill in the Blanks

1. If six times a number equals 72, then the number is ____________.
2. The number x = 3 is the ____________ of the equation 5x – 12 = 3.
y
3. If = 3, then the value of y is ____________.
2
4. A linear equation in two variables has ____________ number of solutions.
5. While solving an equation, an additive constant having positive sign changes to ____________
on transposing it to the other side.
6. One-third of a number minus 1 gives 2. The number is ____________.

Answer in One Word or a Line
1. What is an equation? Is 2x – 3y ≤ 6 an equation?
2. How can we say whether x = k is the solution of a linear equation or not?
3. What is the meaning of transposing a term while solving an equation? In the equation
x
3 = 4, does writing x = 3 × 4 involve transposing 3 on RHS?
4. How many solutions does a linear equation in one variable have?

5. State the four rules that we follow to balance an equation.

let’s evaluate
1. Form an equation in the following cases:

(a) Srishti’s father is 39 years old. He is 4 years older than seven times Srishti’s age. Set up
an equation to find Srishti’s age.
(b) In an isosceles triangle, the base angles are equal. Each of the base angle is half the vertical
angle. Formulate an equation to find the vertical angle x.
2. Give the steps you will use to separate the variable and then solve the equation:
1
(a) 5(x – 2) = 10 (b) x + 4 = 1

3. Solve the following equations by method of transposition and verify your answers:
3(5x – 12)
(a) 2(x – 2) + 3(4x – 1) = 0 (b) 2x – 3 =
10
4. Construct three linear equations starting with the given solution:
–1 –2
(a) m = (b) n =
4 3

5. The sum of three consecutive positive even integers is 90. Find the numbers.
6. Two complementary angles differ by 10°. Find the angles.
7. I am currently 5 times as old as my daughter. In 6 years from now, I will be three times as
old as she will be then. Find our current ages.

8. The length of a field is twice its breadth. If the perimeter of the field is 120 m, find its length
and breadth.
9. In an isosceles triangle, the base angles are equal. The vertex angle is 40°. What are the base
angles of the triangle?

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