Page 46 - Maths Skills - 7

44 Maths

Let’s Attempt

Example 1: Check whether the following equations are satisfied by the given values or not:
(i) a – 3 = 0, a = 3 (ii) 3x + 4 = 7, x = 2
4
(iii) 8 – p = 4, p = 4 (iv) = 2, b = 4
b

Solution: (i) a – 3 = 0 (iii) 8 – p = 4, p = 4
Substituting a = 3 in the LHS we get Substituting p = 4 in the LHS we get

LHS = a – 3 LHS = 8 – p
= 3 – 3 = 0 = 8 – 4 = 4
Thus, LHS = RHS Thus, LHS = RHS
Hence, a = 3 is the Hence, p = 4 is the
solution or root of a – 3 = 0 solution or root of 8 – p = 4
(ii) 3x + 4 = 7, x = 2 (iv) 4 = 2, b = 4
Substituting x = 2, in the LHS we get b

LHS = 3x + 4 Substituting b = 4 in the LHS we get
= 3 × 2 + 4 LHS = 4 = 4 = 1
= 6 + 4 = 10 b 4
Thus, LHS ≠ RHS RHS = 2
Hence, x = 2 is not Thus, LHS ≠ RHS
the solution or root of 3x + 4 = 7 Hence, b = 4 is not the
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solution or root of = 2
b
Example 2: Write the equations for the following statements:
(i) The sum of x and 7 is 12. (ii) One more than twice p is 8.
(iii) Seven times m plus 7 gives 77. (iv) Two less than three-fourth of t is 15.

(v) Four-fifth of a number minus 4 gives 3.
(vi) If you take away 5 from 5 times y, you get 20.

Solution: (i) x + 7 = 12 (ii) 2p + 1 = 8 (iii) 7m + 7 = 77

(iv) 3 t – 2 = 15 (v) 4 x – 4 = 3 (vi) 5y – 5 = 20
4 5

Example 3: Write the following equations in statement forms:
(i) p + 3 = 12 (ii) m – 5 = 2 (iii) 3p + 4 = 26
q
(iv) 3m = 6 (v) 5p – 2 = 18 (vi) + 2 = 2
5 2

Solution: (i) The sum of numbers p and 3 is 12. (ii) The difference of numbers m and 5 is 2.
(iii) Four added to three times p gives 26. (iv) Three-fifth of a number m is 6.
(v) Five times p minus 2 gives 18. (vi) 2 added to half of q gives 2.