agentkronus
agentkronus agentkronus
  • 02-03-2015
  • Mathematics
contestada

Find x when P = 21.

P = x(x - 1) / 2

Respuesta :

konrad509
konrad509 konrad509
  • 02-03-2015
[tex]21=\dfrac{x(x-1)}{2}\\ 42=x^2-x\\ x^2-x-42=0\\ x^2+6x-7x-42=0\\ x(x+6)-7(x+6)=0\\ (x-7)(x+6)=0\\ x=7 \vee x=-6[/tex]
Answer Link

Otras preguntas

If you're currently earning $9.25 per hour and you received a 4% increase, what would be your new hourly rate
Why was the pharaoh's authority never questioned
The hometown team won the national championship. This led to wild celebrations all over the city. Correct the sentence
a natural solid that has its particles arranged in a crystal pattern is called
what is the number 8.293 round on the hundredths
what is 280 divided by 4
what property describes the number sentence 6+0=6
What is the value of x in the equation 0.2(x 1. 0.5x = –0.3(x – 4)?
Four regions in texas from lowest to highest elevation
what is the value the 1 in 214,278,216