16 + (-3) = (n+3) + (-3)
N = 13
Answer:
The base is 4cm and the height is 5cm.
Step-by-step explanation:
This is a solve the system question. Call H the height of the triangle and B the base. The question tells us:

and

Sub the first equation into the second (as H is already isolated). You will end up with a quadratic equation - solve that any way you wish (e.g. quadratic formula). I've provided the factored form below which shows you the roots:

In this question, we take B=4. You can't have a negative side length so the other answer is eliminated. Now sub the value for B into either of the original equations. I'll use the first, again because H is already isolated:

In order to determine the cost of each pencil we have to divide the total cost for the package of pencils by the number of pencils contained
For the 4 pencils box:
Cost per pencil = Total cost/number of pencils
Cost per pencil = 6/4 = 1.5
Similarly, for the 5 pencils package:
Cost per pencil = 7/5 = 1.4
As you can see, the $7 package is better to buy, because each pencil costs $1.4, then, option A is the correct answer