Answer :
Given: a + b = 15
To find: The value of a and b.
Method Used:
To solve the quadratic equation by factorisation method, follow the steps:
1) Multiply the coefficient of x2 and constant term.
2) factorise the result obtained in step 1.
3) Now choose the pair of factors in such a way that after adding or subtracting(splitting) them
You get coefficient of x.
Explanation:
Numbers are ‘a’ and ‘b’
According to given conditions:
a + b = 15
⇒ b = 15 – a …. (1)
Also,
From (1),
⇒ 15 × 10 = 3(15a – a2)
⇒ 15 × 10 = 45a – 3a2
⇒ 3a2 – 45a + 150 = 0
⇒ a2 – 15a + 50 = 0
⇒ a2 – 15a – 5a + 50 = 0
⇒ a (a – 10) – 5(a – 10) = 0
⇒ (a – 5) (a – 10) = 0
⇒ a = 5, 10
If a = 5, b = 15 – 5 = 10
If a = 10, b = 15 – 10 = 5
Hence, Numbers are 5,10 or 10, 5.
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