for what value of x

Question

is the square of the binomial 2x+10 four times greater than the square of the binomial x–5?

is the square of the binomial 2x+10 four times greater than the square of the binomialx–5?

Answer 1

(2x + 10)² = 4(x - 5)²

 

(2x  10)(2x + 10) = 4(x - 5)(x - 5)

 

4x² + 40x + 100 = 4(x² - 10x + 25)

 

4x² + 40x + 100 = 4x² - 40x + 100

 

 

4x² and 100 cancel each outer out, leaving you with

 

40x = -40x

 

40x + 40x = 0

 

80x = 0

 

x = 0

Answer 2

(2x + 10)² = 4x² + 40x + 100

 

(x - 5)² = x² - 10x + 25

 

It is only 4 times greater for x = 0