Question

x = 2/3 and x= -3 arecthe root of quadratic equation ax^2+7x+b=0 find the value of a and b​

Answer 1

Answer:

as x=2/3 then eq will be a(2/3)^2 + 7 (2/3) +b=0-----eq.1

and as x= -3 then eq will be a (-3)^2 +7 (-3) +b=0------eq.2

sub eq.1 and 2:

4/9a+14/3+b=0

9a+21+b=0

- - -

----------------------

-77/9a+77/3=0

77/3=77a/9

it implies that a=3

then put the value of a in eq.2

3 (-3)^2+7 (-3)+b=0

27-21+b=0

6+b=0

b= -6