allerySolve by factorisation: x^2 + 7x + 10 = 0. Roots are
A2 and 5
B-2 and -5
C-1 and -10
D1 and 10
Answer & Solution
Correct answer: B. -2 and -5
1. Look for two numbers whose product is 10 and sum is 7.
2. The pair 2 and 5 fits: 2 * 5 = 10, 2 + 5 = 7.
3. So x^2 + 7x + 10 = (x + 2)(x + 5).
4. Roots: x = -2 and x = -5.
_Source: Selina Concise Mathematics Class 10, Ch 5 Quadratic Equations (Mistral OCR'd PDF), section on factorisation_
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