Simple Equations - Solutions
CSBE Class –VII Mathematics
NCERT Solutions
Simple Equations (Ex. 4.1)
Question 1. Complete the last column of the table:
S. No. | Equation | Value | Say, whether the Equation is satisfied. (Yes / No) |
1 |
| ||
2 |
| ||
3 |
| ||
4 |
| ||
5 |
| ||
6 |
| ||
7 |
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8 |
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9 |
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10 |
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11 |
|
Answer:
S. No. | Equation | Value | Say, whether the Equation is satisfied. (Yes / No) |
1 | No | ||
2 | No | ||
3 | Yes | ||
4 | No | ||
5 | Yes | ||
6 | No | ||
7 | Yes | ||
8 | No | ||
9 | No | ||
10 | No | ||
11 | Yes |
Question 2.Check whether the value given in the brackets is a solution to the given equation or not:
(a)
(b)
(c)
(d)
(e)
(f)
Answer: (a)
Putting in L.H.S.,
1 + 5 = 6
L.H.S. R.H.S.,
is not the solution of given equation.
(b)
Putting in L.H.S.,
L.H.S. R.H.S.,
is not the solution of given equation.
(c)
Putting in L.H.S.,
L.H.S. R.H.S.,
is the solution of given equation.
(d)
Putting in L.H.S.,
L.H.S. R.H.S.,
is not the solution of given equation.
(e)
Putting in L.H.S.,
L.H.S. R.H.S.,
is not the solution of given equation.
(f)
Putting in L.H.S.,
L.H.S. R.H.S.,
is not the solution of given equation.
Question3.Solve the following equations by trial and error method:
(i)
(ii)
Answer: (i)
Putting in L.H.S. =
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is the solution.
(ii)
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is not the solution.
Putting in L.H.S.
Therefore, is the solution.
Question 4. Write equations for the following statements:
(i) The sum of numbers and 4 is 9.
(ii) 2 subtracted from is 8.
(iii) Ten times is 70.
(iv) The number divided by 5 gives 6.
(v) Three-fourth of is 15.
(vi) Seven times plus 7 gets you 77.
(vii) One-fourth of a number minus 4 gives 4.
(viii) If you take away 6 from 6 times you get 60.
(ix) If you add 3 to one-third of you get 30.
Answer: (i)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
(viii)
(ix)
Question 5. Write the following equations in statement form:
(i)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
(viii)
Answer: (i) The sum of numbers and 4 is 15.
(ii) 7 subtracted from is 3.
(iii) Two times is 7.
(iv) The number is divided by 5 gives 3.
(v) Three-fifth of the number is 6.
(vi) Three times plus 4 gets 25.
(vii) If you take away 2 from 4 times you get 18.
(viii) If you added 2 to half is you get 8.
Question 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. (Tale 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 years.)
(iii) The teacher tells the class that the highest marks obtained by a student in her class are twice the lowest marks plus 7. The highest score is 87. (Take the lowest score to be )
(iv) In an isosceles triangle, the vertex angle is twice either base angle. (Let the base angle be in degrees. Remember that the sum of angles of a triangle is )
Answer: (i) Let be the number of Parmit’s marbles.
(ii) Let the age of Laxmi be years.
(iii) Let the lowest score be
(iv) Let the base angle of the isosceles triangle be so vertex angle =
[Angle sum property of a ]