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

A system of linear equations is given as follows :
a1x+b1y+c1=0
a2x+b2y+c2=0
Condition for two lines to have infinitely many solutions is,

A
a1a2=b1b2=c1c2
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
a1a2c1c2
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
a1a2=b1b2c1c2
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
None of these
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B a1a2=b1b2=c1c2
Letustaketwoequationsas
a1x+b1y+c1=0........(i)anda2x+b2y+c2=0.......(ii).

Ifthereareinfinitemanysolutionsthelinesshouldcoincide.Forcoincidenceofthelinestheslopesofthetwoequationsshouldbeequalandtheinterceptsofthetwoequationsshouldbeequal.

Wrtingtheequationsinslopeinterceptformwehave,

(i)asy=a1b1x+(c1b1)and(ii)asy=a2b2x+(c2b2).


Nowifthelinescoincidethentheslopesareequal.i.ea1b1=a2b2a1a2=b1b2........(iii).


Alsotheinterceptsareequal.i.e(c1b1)=(c2b2)c1c2=b1b2......(iv).


Comparing(iii)&(iv)wehavea1a2=b1b2=c1c2.

AnsOptionA.

flag
Suggest Corrections
thumbs-up
2
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Graphical Solution
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon