(a) 3n – 2 = 46
Step 1 :
3n – 2+2= 46+2
3n=48
Step 2 :
\(\frac{3n}{3}\)=\(\frac{48}{3}\)
\(\Rightarrow n=16\)
(b) 5m+7=17
Step 1 :
5m+7-7=17-7
\(\Rightarrow 5m=10\)[Subtracting 7 both sides]
Step 2 :
\(\frac{5m}{5}=\frac{10}{5}\)[Dividing both sides by 5]
\(m=2\)
(c) \(\frac{20p}{3}\) =40
Step 1 :
\(\frac{20p}{3}\times 3\) =40\(\times 3\) [Multiplying both sides by 3]
Step 2 :
\(\frac{3p}{3}=\frac{60}{3}\)
\(\Rightarrow p=20\) [Dividing both sides by 20]
(d) \(\frac{3p}{10}\)=6
Step 1 :
\(\frac{3p}{10}\times 10\)=\(6\times 10\)
\(\Rightarrow 3p=60\) [Multiplying both sides by 10]
Step 2 :
\(\frac{3p}{3}=\frac{60}{3}\)
\(p=20\) [Dividing both sides by 3]
Solve the following equations by trial and error method: (i) 5p + 2 = 17 (ii) 3m – 14 = 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
Match the items given in Column I with one or more items of Column II.
Column I | Column II |
(a) A plane mirror | (i) Used as a magnifying glass. |
(b) A convex mirror | (ii) Can form image of objects spread over a large area. |
(c) A convex lens | (iii) Used by dentists to see enlarged image of teeth. |
(d) A concave mirror | (iv) The image is always inverted and magnified. |
(e) A concave lens | (v) The image is erect and of the same size as the object. |
- | (vi) The image is erect and smaller in size than the object. |