Page 156 - ICSE Math 7

(b) Two supplementary angles are such that one is 60° less than the other. Which of the following
is greater of the two angles?
(i) 60° (ii) 80° (iii) 100° (iv) 120°

(c) Which of the following equations is true for x = –3?
(i) 2x + 8 = 2 (ii) 2x + 8 = 3 (iii) 2x + 7 = 2 (iv) 5x = 14

2. Write True or False.
(a) In a linear equation, the maximum power of a variable is one.
(b) A linear equation in one variable can have many solutions.
(c) While solving an equation, we can multiply one side and divide the other by the same constant.

(d) From a given solution, infinite number of equations can be constructed.
(e) To balance an equation, we have to perform the same operation on both sides.

3. Fill in the blanks.
(a) If six times a number equals 72, then the number is ____________.
(b) The number x = 3 is the ____________ of the equation 5x – 12 = 3.
y
(c) If = 3, then the value of y is ____________.
2
(d) A linear equation in two variables has ____________ number of solutions.

(e) While solving an equation, an additive constant having positive sign changes to ____________
on transposing it to the other side.

PRACTICE TIME

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 + = 1
4
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. Solve the following equations.
1
z
z
(a) 7(x – 2) = 3(x – 5) (b) 3x + 5 = 4x – 3 (c) – = 10
2
5
4x + 3 4
(d) 6(2x – 1) – 1 = 5(3x – 5) (e) =
3x + 5 5
6. The sum of three consecutive positive even integers is 90. Find the numbers.

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