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

A Find the value of x. 6 X B D x = [?] 8 4 C
PLEASE HELP True or false
How is inspiration different from motivation? Give an example. Each should be a complete paragraph (3-5 sentences).
which statement accurately describes the relationship between price and quantity demanded? A. when prices increase, quantity demanded decreases B. when prices
binomial expansion of (2+3x)^5
Choose the correct simplification of the expression (2x7y)2(y5)3.
The length of an arc of a circle is 7.34 units, and the measure of the corresponding central angle is 81°. What is the approximate length of the radius of the c
HELP THIS IS URGENT I NEED IT SOON! PLEASE If f(x) = x2 − 6x − 4 and g(x) = 5x + 3, what is (f + g)(−3)? 41 35 11 −35
there are 20nstudents in a math class who have brown hair this represent 80 percent of the students in the class with equation can be used to find the total os
What would the slope of a line be if it were parallel to the line: y = 1 / 3x - 5 ?