(i) x+7+4(x–5) = x+7+4x-20=x+4x+7-20 = 5x-13 = 5×2-13 = 10-13 = -3 [putting x = 2]
(ii) 3(x+2)+5x–7 = 3x+6+5x-7 = 3x+5x+6-7 = 8x-1 = 8×2-1 = 16-1 = 15 [putting x = -1]
(iii) 6x+5(x–2) = 6x+5x-10 = 11x-10 = 11×2-10 = 22-10 = 12 [putting x = -1]
(iv) 4(2x–1)+3x+11 = 8x-4+3x+11 = 8x+3x-4+11 = 11x+7 = 11×2+7 = 22+7 = 29 [putting x = -1]
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. |