jahajahaja jahajahaja
  • 01-09-2016
  • Mathematics
contestada

What are the zeros of f(x)=x^2+x-20?
A.x=-2 and x=10
B.x=-10 and x=2
C.x=-5 and x=4
D.x=-4 and x=5

Respuesta :

dalendrk
dalendrk dalendrk
  • 02-09-2016
f(x) = x² + x - 20 = x² + 5x - 4x - 20 = x(x + 5) - 4(x + 5) = (x + 5)(x - 4)

f(x) = 0 ⇔ (x + 5)(x - 4) = 0 ⇔ x + 5 = 0 or x - 4 = 0 ⇒ x = -5 or x = 4

Answer: C. x = -5 and x = 4.
Answer Link

Otras preguntas

Why were the committees of correspondence powerful?
What is the additive inverse of -4a
The type and age of rocks found in the mountain range are also found on another continent. What might this mean?
Step by step directions Square root for 480
what is the percent change from 70 to 56?
Which sentence does not contain any errors in comma usage? A. If you ever visit New Haven, Connecticut, be sure to eat at Sally's Pizza. B. The original Londo
Which of the following is NOT a form of formal debate? A. an argument B. policy debate C. parliamentary debate D. Lincoln-Douglass debate
p(x) x^3+x^2-x-1 Find all zeros of p (x)
Solve 2x2 - 8x = -7 Which of the following is a solution of x2 + 5x = -2?
why did russia have revolution in 1917?