JAMB - Mathematics (2015 - No. 3)
Factorize x2 + 9x + 20
(x − 5) 2
(x + 5)(x + 4)
(x – 5)(x + 3)
(x + 3) 2
Explanation
\( x^2 + 9x + 20 \)
Find the two numbers whose product is 20 and its sum is 9}
\( 5x \times 4x = 20x^2\)
\(5x + 4x = 9x\)
\((x^2 + 5x) + (4x + 20)\)
\(
x(x + 5)+ 4(x + 5)
= (x + 5)(x + 4)\)
Find the two numbers whose product is 20 and its sum is 9}
\( 5x \times 4x = 20x^2\)
\(5x + 4x = 9x\)
\((x^2 + 5x) + (4x + 20)\)
\(
x(x + 5)+ 4(x + 5)
= (x + 5)(x + 4)\)
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