Question
If ‘y1’ and ‘y2’ are the roots of quadratic
equation 5y2 – 25y + 15 = 0, then find the quadratic equation whose roots are ‘3y1’ and ‘3y2’.Solution
For an equation of the form ax2 + bx + c = 0, Sum of roots = (-b/a) Product of roots = (c/a) Sum of roots (y1 + y2) = – (–25/5) = –(–5) = 5 Product of roots (y1 × y2) = (15/5) = 3 Sum of roots of required equation = 3y1 + 3y2 = 3 × (y1 + y2) = 3 × 5 = 15 Product of roots of required equation = 3y1 × 3y2 = 9 × y1 × y2 = 9 × 3 = 27 Quadratic equation is: y2 – (sum of roots) × y + (product of roots). So, required equation = y2 – 15y + 27 = 0
Train 'P' travels at a speed of 45 km/h and crosses train 'Q' in 15 seconds while moving in opposite directions. Determine the speed of train 'Q' if the...
? = (7.11/2.12) + (10.88/4.09) + (45.12/11.98)
24.99 × 32.05 + ? - 27.01 × 19.97 = 29.99 × 27.98
24.99 × 32.05 + ? - 27.01 × 19.97 = 29.99 × 27.98
- What approximate value will come in place of the question mark (?) in the following question? (Note: You are not expected to calculate the exact value.)
What approximate value should come in the place of (?) in the following questions?
9.9 * [? – (4.9 * √576 ÷ 7.80)] = 950.05
(27.08)2 – (14.89)2 – (22.17)2 = ?
( 1000)1/3  × 10.11 × 4.97 ÷ 10.32 =? – 15.022
1649.98 ÷ 15.48 × 8.12 = ? × 8.16