Solve the following equations by trial and error method: (i) 5p + 2 = 17 (ii) 3m – 14 = 4
Solve the following equations by trial and error method: (i) 5p + 2 = 17 (ii) 3m – 14 = 4
Solution and Explanation
(i)5p+2=17.
L.H.S=5p+2
By putting, p=0,
we get
5(0)+2=2≠17
By putting, p=1,
we get
5(1)+2=7≠17
By putting,p=2,
we get
5(2)+2=12 L.H.S≠ R.H.S
By putting, p=3,
we get
5(3)+2=17
L.H.S = R.H.S
So, p = 3is a solution of the equation.
ii) 3m–14=4
3m–14= L.H.S
By putting,m=5,
we get
3(5)–14=1≠6
By putting, m=6,
we get
3(6)–14=4
L.H.S= R.H.S. Therefore, m = 6 is a solution of the equation.
Top Questions on A Mind-Reading Game
- Set up equations and solve them to find the unknown numbers in the following cases:
(a) Add 4 to eight times a number; you get 60.
(b) One-fifth of a number minus 4 gives 3.
(c) If I take three-fourths of a number and add 3 to it, I get 21.
(d) When I subtracted 11 from twice a number, the result was 15.
(e) Munna subtracts thrice the number of notebooks he has from 50, he finds the result to be 8.
(f) Ibenhal thinks of a number. If she adds 19 to it and divides the sum by 5, she will get 8.
(g) Anwar thinks of a number.If he takes away 7 from \(\frac{5}{2}\) of the number,the result is 23.- CBSE Class VII
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(b) x + 1 = 0
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(d) x + 6 = 2
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(f) y – 4 = 4
(g) y + 4 = 4
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(i)p+4=15
(ii)m-7=3
(iii)2m=7
(iv)\(\frac{m}{5}\)=3
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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.
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(ix) If you add 3 to one-third of z, you get 30- CBSE Class VII
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(f)3s=-9
(g)3s+12=0
(h)3s=0
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(j)2q-6=0
(k)2q+6=0
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Questions Asked in CBSE Class VII exam
Convert the given fractional numbers to per cents.
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(i) Which number is the highest?
(ii) Which number is the lowest?
(iii) What is the range of the data?
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