Question

if x=2/3 andx=-3 are roots of the quadratic equation axroot+7x+b=0find the values of a and b

Answer 1

when x=2/3
$4 \div 9 a + 14 \div 3+ b = 0$
(4a+42+9b)=0
4a+9b= -42--------------(eq . 1)

when x=-3
9a-21+b=0
b=21-9a---------------(eq. 2)

On putting it in eq 1
4a+9 (21-9a)= -42
4a+189-81a=-42
-77a=-231
a=231/77=3
hence a= 3

Now to find b put value of a in eq 2

b=21-9a
b=21-9 (3)=21-27=-6

Therefore, a=3 ; b= -6

Hope it helps!!!!!