3y2 + 7y + 4 = 0


(vii) 3y2 + 7y + 4 = 0
Sol.  3y2 + 7y + 4 = 0
Comparing with ax2 + bx + c = 0 we have a = 3, b = 7, c = 4
b2 – 4ac = (7)2 – 4 (3) (4)
= 49 – 48
= 1
By Formula method,
y
=
-  b ± √(b2 – 4ac)




2a







∴ y
=
-(7) ± √1




2(3)







∴ y
=
-7 ± 1




6







∴ y
=
-7 + 1
or
-7 – 1


6

6





∴ y
=
-6
or
-8


6

6





∴ y
=
-1
or
-4/3