Advertisements
Advertisements
प्रश्न
If the equation `9x^26kx+4=0` has equal roots then k =?
(a)1 or (b)-1 or 4 (c)1 or -4 (d)-1 or -4
उत्तर
(a) `1 or 4`
It is given that the roots of the equation `(x^2+2(k+2)x+9k=0)` are equal.
∴`(b^2-4ac)=0`
⇒`{2(k+2)}^2-4xx1xx9k=0`
⇒`4(k^2+4k+4)-36k=0`
⇒`4k^2+16k+16-36=0`
⇒`4k^2-20+16=0`
⇒`k^2-5k+4=0`
⇒`k^2-4k-k+4=0`
⇒`k(k-4)-(k-4)=0`
⇒`(k-4) (k-1)=0`
⇒` k=4 or k=1`
APPEARS IN
संबंधित प्रश्न
(a) `3x-x^2=x^2+5` (b) `(x+2)^2=2(x^2-5)`
(c) `(sqrt2x+3)^2=2x^2+6` (d)` (x-1)^2=3x^2+x-2`
Solve` 2x^2+ax-a^2=0`
Solve `3x^2+5sqrt5x-10=0`
Write the following equation in the form ax2 + bx + c= 0, then write the values of a, b, c for the equation.
x2 + 5x = –(3 – x)
Choose the correct answer for the following question.
Which of the following quadratic equations has roots 3,5?
Choose the correct answer for the following question.
Out of the following equations, find the equation having the sum of its roots –5.
Choose the correct answer for the following question.
One of the roots of equation x2 + mx – 5 = 0 is 2; find m.
If P(y) = y² - 2y + 5, find P(2) .
Write the degree of Polynomial 5x2 + 2x + 3x4 + 4.
A boat goes 30 km upstream and 44 km downstream in 10 hours. In 13 hours, it can go 40 km upstream and 55 km downstream. Determine the speed of the stream and that of the boat in still water.
