Question

5x^2-7x-6=0 by using completely square method

Answer 1

Answer:

{ - 0.6, 2 }

Step-by-step explanation:

(a ± b)² = a² ± 2ab + b²

a² - b² = (a - b)(a + b)

~~~~~~~~~~~~

5x² - 7x - 6 = 0

x² - $\frac{7}{5}$ x - $\frac{6}{5}$ = 0

x² - 2 × $\frac{7}{10}$ x + ( $\frac{7}{10}$ )² - $\frac{49}{100}$ - $\frac{6}{5}$ = 0

(x - $\frac{7}{10}$ )² - ( $\frac{169}{100}$ ) = 0

(x - $\frac{7}{10}$ )² - ( $\frac{13}{10}$ )² = 0

(x - $\frac{7}{10}$ - $\frac{13}{10}$ )(x - $\frac{7}{10}$ + $\frac{13}{10}$ ) = 0

(x - 2)(x + 0.6) = 0

$x_{1}$ = 2

$x_{2}$ = - 0.6

x ∈ { - 0.6, 2 }