Exercise 9.2
Contents
Solve each of the following equations and also check your result in each case:
16. 0.18(5x – 4) = 0.5x + 0.8
Solution:
0.18(5x – 4) = 0.5x + 0.8
=> 0.9x – 0.72 = 0.5x + 08
=> 0.9x – 0.5x = 0.8 + 0.72
=> 0.4x = 1.52
= x =
= 3.8
Verify
L.H.S= 0.18(5(3.8) – 4) = 0.18 × 15 = 2.7
R.H.S = 0.5(3.8) + 0.8 = 2.7
Therefore, L.H.S= R.H.S
24. (3x – 8) (3x + 2) – (4x – 11) (2x + 1) = (x – 3) (x + 7)
Solution:
(3x – 8) (3x + 2) – (4x – 11) (2x + 1) = (x – 3) (x + 7)
= 9x2+6x–24x–16–8x2–4x+22x+11=x2+7x–3x–21
= x2–5=x2+4x–21
= 4x = 21 – 5
= 4x = 16
= x = 164
= 4
Verify:
L.H.S = (3(4) – 8) (3(4) + 2) – (4(4) – 11) (2(4) + 1) = 4(16) – 5(9) = 11
R.H.S = (4 – 3) (4 + 7) = 11
Therefore, L.H.S = R.H.S