Question

Find all real zeros of the function algebraically -5(x^2+2x-4)

Answer 1

`−5(²+2−4)`

`−5²−10+20`

Solution :—

`−5²−10+20`

Answer 2

Explanation:

-5(x² + 2x - 4) = -5x² - 10x + 20

a = -4 ; b = -10 ; c = 20

D = b² - 4ac = (-10)² - 4*(-4)*20

= 100 + 320 = 420

`√(D)=√(2*2*3*5*7)=2√(105)\\\\x=(-b+√(D))/(2a) \ ; x =(-b-√(D))/(2a)\\\\\\x=(10+2√(105))/(2*(-5)) \ ; \ x =(10-2√(105))/(2*(-5))\\\\\\x = (2*(5+√(105)))/(2*(-5)) ; \ x =(2*(5-√(D)))/(2*(-5))\\\\\\x =(5+√(105))/(-5) \ ; \ x=(5-√(105))/(-5)\\\\\\x=(-5-√(105))/(5) \ ; \ x =(-5+√(105))/(5)`