(a) n + 5 = 19; (n = 1)

(b) 7n + 5 = 19; in – -2)

(c) 7n + 5 = 19; (n = 2)

(d) 4p – 3 = 13; (p = 1)

(e) 4p – 3 = 13; (p = -4)

(f) 4p-3 = 13; (p = 0)

Answer :

(a) n + 5 = 19 (n = 1)
Put n = 1 in LHS

1 + 5 = 6

RHS =19

Since LHS ? RHS

Thus n = 1 is not the solution of the given equation. "n+5=19"

(b) 7n + 5 = 19 (n = -2)
Put n = -2 in LHS

-2×7 + 5 = -9

RHS =19

Since LHS \(\neq \)RHS

Thus n = -2 is not the solution of the given equation. "7n+5=19"

(c) 7n + 5 = 19 (n = 2)
Put n = 2 in LHS

7×2 + 5 = 19

RHS =19

Since LHS = RHS

Thus n = 2 is the solution of the given equation. "7n+5=19"

(d) 4p-3 = 13 (p= 1)
Put p = 1 in LHS

4×1-3 = 1

RHS =13

Since LHS \(\neq \)RHS

Thus p = 1 is not the solution of the given equation. "4p-3=13"

(e) 4p - 3= 13 (p = -4)
Put p = -4 in LHS

4×(-4) - 3 = -19

RHS =13

Since LHS \(\neq \)RHS

Thus p = -4 is not the solution of the given equation. "4p-3=13"

(f) 4p-3=13 (p= 0)
Put p = 0 in LHS

0×4-3 = -3

RHS =13

Since LHS \(\neq \) RHS

Thus p = 0 is not the solution of the given equation. "4p-3=13"

- Q.1 Complete the last column of the table.
- Q.3 Solve the following equations by trial and error method: (i) 5p + 2 = 17 (ii) 3m – 14 = 4
- Q.4 Write equations for the following statements: (i) The sum of numbers x and 4 is 9. (ii) 2 subtracted from y is 8. (iii) Ten times a is 70. (iv) The number b divided by 5 gives 6. (v) Three-fourth of t is 15. (vi) Seven times m plus 7 gets you 77. (vii) One-fourth of a number x minus 4 gives 4. (viii) If you take away 6 from 6 times y, you get 60. (ix) If you add 3 to one-third of z, you get 30.
- Q.5 Write the following equations in statement forms: (i) p + 4 = 15 (ii) m-7=3 (Iii) 2m=7 (iv) m/5= 3 (v) 3m/5=6 (vi) 3p+4=25 (vii) 4p -2 =18 (viii) p/2+2=8
- Q.6 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’s marbles) (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) (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) (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).

- NCERT solutions for class 7 maths chapter 1 Integers
- NCERT solutions for class 7 maths chapter 2 Fractions and Decimals
- NCERT solutions for class 7 maths chapter 3 Data Handling
- NCERT solutions for class 7 maths chapter 4 Simple Equations
- NCERT solutions for class 7 maths chapter 5 Lines and Angles
- NCERT solutions for class 7 maths chapter 6 The Triangle and its Properties
- NCERT solutions for class 7 maths chapter 7 Congruence of Triangles
- NCERT solutions for class 7 maths chapter 8 Comparing Quantities
- NCERT solutions for class 7 maths chapter 9 Rational Numbers
- NCERT solutions for class 7 maths chapter 10 Practical Geometry
- NCERT solutions for class 7 maths chapter 11 Perimeter and Area
- NCERT solutions for class 7 maths chapter 12 Algebraic Expressions
- NCERT solutions for class 7 maths chapter 13 Exponents and Powers
- NCERT solutions for class 7 maths chapter 14 Symmetry
- NCERT solutions for class 7 maths chapter 15 Visualising Solid Shapes

- NCERT solutions for class 7 science chapter 1 Nutrition in Plants
- NCERT solutions for class 7 science chapter 2 Nutrition In Animals
- NCERT solutions for class 7 science chapter 3 Fibre to Fabric
- NCERT solutions for class 7 science chapter 4 Heat
- NCERT solutions for class 7 science chapter 5 Acids Bases and Salts
- NCERT solutions for class 7 science chapter 6 Physical and Chemical Changes
- NCERT solutions for class 7 science chapter 7 Weather, Climate and Adaptations of Animals to Climate
- NCERT solutions for class 7 science chapter 8 Winds, Storms and Cyclones
- NCERT solutions for class 7 science chapter 9 soil
- NCERT solutions for class 7 science chapter 10 Respiration in Organisms
- NCERT solutions for class 7 science chapter 11 Transportation in Animals and Plants
- NCERT solutions for class 7 science chapter 12 Reproduction In Plant
- NCERT solutions for class 7 science chapter 13 Motion and Time
- NCERT solutions for class 7 science chapter 14 Electric Current and Its Effects
- NCERT solutions for class 7 science chapter 15 Light
- NCERT solutions for class 7 science chapter 16 Water: A Precious Resource
- NCERT solutions for class 7 science chapter 17 Forests: Our Lifeline
- NCERT solutions for class 7 science chapter 18 Waste Water Story