agentkronus agentkronus

02-03-2015
Mathematics

contestada

Find x when P = 21.

P = x(x - 1) / 2

Respuesta :

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

8. Ms. Kennedy wants to buy a new interactive whiteboard for her classroom that costs $989. So far, Ms. Kennedy has collected $485 in donations, and $106 in fun

which event would most likely lead to a thunder storm

Glen has called his landlord about some flickering lights and outlets that do not work at all. He comes home from a weekend trip to his apartment surrounded by

Ms. Garcia's science students are studying scale models. For her science project, Sarah has decided to make a scale model of the solar system. Sarah conducted s

For the following equation insert the correct coefficients that would balance the equation. If no coefficient is need please insert the NUMBER 1. 4. C2H6 + O2

When appraising a property your goal is: a. Establish the highest possible price that a property can sell for b. Establish the most probable price that would be

Hudson is making smoothies. Each smoothie uses 2/3 cup of yogurt. How many cups of yogurt does he need to make 16 smoothies? Express your answer in simplest for

What it the length of the leg

A brother and a sister are in the same math class. There are 8 boys in the class and there are 10 girls in the class. If one boy and one girl are chosen at rand

The graph of a function f is shown below. Find f (2) and find one value of x for which f(x) = -4