EXERCISE 13.3 Q NO. 6 AND 7

Q 7 Ex-3.5 | STD 6 MATHS | Chap-3: PLAYING WITH NUMBERS| PART-26 | NCERT |

For solving each pair of equations, in this exercise, use the method of elimination by equating coefficients : 13 + 2y = 9x 3y = 7x

Find the mode of (i) 7, 7, 8, 10, 10, 11,13, 14 (ii) 4, 5, 6, 7, 8, 7, 6, 5, 3, 4, 6, 7, 6

Evaluate: -3/8 + 5/8 + 7/8 , (ii) 11/3 + -5/3 + -2/3 , (iii) -1+ 2/(-3) + 5/6 , (iv) 7/26 + (-11)/13 + 2 , (v) 3+(-7/8) + -3/4 , (vi) -13/8 + 7/16 + (-3)/4

Find : (i) 7/3 -: 2 (ii) 4/9 -: 5 (iii) 6/13 -: 7 (iv) (4) 1/3 -: 3 (v) (3)1/2 -: 4 (vi) (4) 3/7 -: 7

Which of the following is an orthogonal matrix ? ( ⎡ ⎢ ⎣ 6 / 7 2 / 7 − 3 / 7 2 / 7 3 / 7 6 / 7 3 / 7 − 6 / 7 2 / 7 ⎤ ⎥ ⎦ (b) ⎡ ⎢ ⎣ 6 / 7 2 / 7 3 / 7 2 / 7 − 3 / 7 6 / 7 3 / 7 6 / 7 − 2 / 7 ⎤ ⎥ ⎦ (c) ⎡ ⎢ ⎣ − 6 / 7 − 2 / 7 − 3 / 7 2 / 7 3 / 7 6 / 7 − 3 / 7 6 / 7 2 / 7 ⎤ ⎥ ⎦ (d) ⎡ ⎢ ⎣ 6 / 7 − 2 / 7 3 / 7 2 / 7 2 / 7 − 3 / 7 − 6 / 7 2 / 7 3 / 7 ⎤ ⎥ ⎦

If |x+3|geq10 , then x in (-13 ,\ 7] b. x in (-oo,-13)uu(7,oo) c. x in (-13 ,7) d. x in (-oo,\ -13]uu[7,oo)

Show that the points P(7,3) , Q ( 6,3+ sqrt3) and R (5,3) from an equilateral triangles.

If x = (1.3)/(3.6) + (1.3.5)/(3.6.9) + (1.3.5.7)/(3.6.9.12) + ….. then prove that 9x^2 + 24x = 11

Find the missing frequency for the following distribution whose mean is 7.68 3 5 7 9 11 13 6 8 15 8 4