Question

If a+b=9 and ab=20 find the value ofa,b

Answer 1

Answer:

a and b are 4 and 5

Explanation:

a+b=9

b=9-a --------(1)

We know ab=20

Substitute (9-a) in the place of b

a(9-a)=20

9a-a²=20

Multiplying both sides by -1

a²-9a=-20

a²-9a+20=0

Here, we get a quadratic equation.

Solving using factorization method.

a²-9a+20=0

(a-4)(a-5)=0

Therefore,

(a-4)=0

a=4

(a-5)=0

a=5

When a=4, b=9-4=5

When a=5, b=9-5=4

So we can conclude that values of a and b are 4 and 5.

Thank you.

Answer 2

Answer:

Step-by-step explanation:

from the given question,

a+b=9

ab=20

a+b=9

a=b-9

b=b

then, a×b=(b-9)×b=b²+9b=20

now find a number which agrees with the above statement, which will be value of b

THEN YOU CAN FIND VALUE OF A AND B