Answer:
Cost of one pencil: 
Cost of one eraser: 
Step-by-step explanation:
Let be "p" the cost in dollars of one pencil and "e" the cost in dollars of one eraser.
Based on the information given in the exercise, you can set up the following system of equations:

You can use the Elimination Method to solve the system of equations.
Multiply the first equation by -3 ad the second one by 4. Then add the equations and solve for "e":
{
Substitute the value of "e" into any original equation and solve for "p":

These problems really aren't hard just set them equal to each other and see if what they are saying is true. Are they equal? Do they both equal 0?
Answer:
I only
Step-by-step explanation:
dy/dx = x + 1 / y -3
(y - 3)dy = (x + 1) dx
integrate
1/2y^2 - 3x = 1/2x^2 + x
1/2y^2 = 1/2x^2 + 4x
y^2 = x^2 + 8x
y = (x^2 + 8x)^1/2
Answer:
320 pesos
Step-by-step explanation:
Un 20% de descuento en formato decimal es 0.20. La totalidad de la bicicleta es representada como 100% o 1 y nosotros queremos saber el precio despues del descuento que seria
100% - 20% = 80% o 0.80
Ahora simplemente multiplicamos este decimal por el valor original de la bicicleta para saber el precio descontado...
400 * 0.80 = 320 pesos
Answer:
Option 4
Step-by-step explanation: