wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

If the equation x2+2(k+2)x+9k=0 has real equal roots, then values of k are

A
1 and 4
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
1 and 5
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
1 and 5
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is A 1 and 4
On comparing x2+2(k+2)x+9k=0 with standard form ax2+bx+c=0, we get

a = 1, b = 2(k + 2) and c = 9k

For, x2+2(k+2)x+9k=0, value of discriminant,

D=b24ac

D=4(k+2)24(9k)
The roots of quadratic equation are real and equal only when discriminant, D=0.

4(k+2)24(9k)=0

(k+2)2=9kk25k+4=0k24kk+4=0k2k4k+4=0k(k1)4(k1)=0(k4)(k1)=0k=4 or 1

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon