Question

Q. 4. If one root of the equation ax^2 - 7x + 12 = 0 is 3, then find value of a.​

Answer 1

ax² -7x +12 = 0

putting the value of x

a(3)² -7(3) +12 = 0

9a -21 +12 = 0

9a = 9

a = 1

Answer 2

Given

one of the root of the Equation ax²-7x+12=0 is 3

To Find

value of a

$\sf\huge\bold{\underline{\underline{{Solution}}}}$

Step by step explanation:

1. We have given one root which is x=3 .So ,put 3 into the Equation where a remains constant.
2. Equate and solve the Equation equals to zero we will find the value of 'a'.

=>ax²-7x +12=0

put x = 3 into equation

=>a(3)²-7(3)+12=0

=>9a-21+12=0

=>9a -9=0

=>9a=9

=>a=9/9=1

a=1

Therefore,the value of a is 1

Check:

=>ax²-7x+12=0

=>1x²-7x+12=0

=>x²-7x+12=0

=>x²-4x-3x+12=0

=>x(x-4)-3(x-4)=0

=>(x-3)(x-4)=0

x-3=0

x= 3

x-4=0

x=4

Therefore, the roots are x= 3 & x= 4

ax²-7x+12=0

=>1(3)²-7(3)+12

=>9-21+12

=>9-9=0