Answer:
El primer paso será darle un nombre a nuestras variables:
x= Numero de libros comprados inicialmente
y=Precio inicial de los libros
Ahora analizamos el enunciado,
Lorena ha comprado libros todos del mismo precio por valor de 120 €
x*y=120 € (1)
El librero le regala 3 libros por lo que en realidad cada libro que cuesta 2 € menos
(x+3)(y-2)=120€ (2)
Tenemos entonces dos ecuaciones con dos incógnitas, así que podemos resolver,
Despejamos en (1)
x=120/y
Sustituimos en (2)
(120/y +3)(y-2)=120
120 - 240/y + 3y -6 =120
3y-240/y =120-120+6
3y -240/y =6
y- 80/y=6
y²-80=6y
y²-6y-80=0
Resolvemos la ecuación de segundo grado
a=1
b=-6
c=-80
Aplicando la resolvente,
(6+- √36+320)/2
6+-√356/2
(6+-18,86)/2
Como el valor de y no puede ser negativo la unica respuesta válida será:
y=12,43
Cada libro le costo 12,43€
Sustituyendo en (1)
x=120/12,43
x=9,65 como no puede ser un número racional
x=9
Lorena ha comprado 9 libros
Answer:
Step-by-step explanation:
the polynomial function is; (x - i)(x-2)(x+2)
Answer:
14130 yd^3
Step-by-step explanation:
The volume of a sphere is
V = 4/3 pi r^3
The diameter is 30 so the radius is d/2 = 30/2 = 15
V = 4/3 pi (15)^3
V = 4500 pi
Letting pi = 3.14
V = 14130 yd^3
First lets take away the negative sign for now
Now lets separate the number into its two components which are 11 and 0.16
Now lets rewrite it to 16/100
Next we want to find the greatest common factor between 16 and 100 which is 4 since 4 * 4 equals 16 and 4 * 25 equals 100 so its 4.
Now lets divide 16 and 100 by the greatest common factor so its sixteen divided by 4 over 100 divided by 4
Next we simplify all together which is 4/25
You remember that number 11 we had earlier, well we are going to go grab him back and add him to the fraction and make it 11 4/25 but... remember that negative sign, I said for now, right, so lets put him back on the spotlight.
Answer: -11 4/25