One of the factors of (2x + 5y)² - 5 (2x + 5y) - 14

Correct Answer is : 2x+5y−72x + 5y - 72x+5y−7

Correct Answer is : 2x+5y−72x + 5y - 72x+5y−7

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CTET Paper II (Mathematics and Science) May 2016 Solved Paper

Question : 32 of 150

Marks: +1, -0

(2x + 5y)^{2} - 5 (2x + 5y) - 14

Solution:

Concept:

Factor a quadratic in one variable by substituting a single term for the expression.

Explanation:

Let

u = 2x + 5y

. The expression becomes

u^2 - 5u - 14

Factor this quadratic:

u^2 - 5u - 14 = (u - 7)(u + 2)

Substitute back:

(2x + 5y - 7)(2x + 5y + 2)

Thus one factor is

2x + 5y - 7

Answer:

2x + 5y - 7

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