x^2 - 7x + 15
_________________
(x+4)/ x^3 - 3x^2 - 13x + 78
- x^3 + 4x^2
----------------
- 7x^2 - 13x
- - 7x^2 - 28x
------------------
15x + 78
- 15x + 60
-------------
18
remainder = 18
The height of a triangle is 9 cm
<h3>
What is Triangle?</h3>
- A polygon with three edges and three vertices is called a triangle. It is one of the fundamental geometric shapes. Triangle ABC is the display style for a triangle with vertices A, B, and C.
- In Euclidean geometry, any three points that are not collinear produce a singular triangle and a singular plane (i.e. a two-dimensional Euclidean space).
- In other words, every triangle is contained in a plane, and there is only one plane that contains that triangle.
- All triangles are enclosed in a single plane if all of the geometry is the Euclidean plane, however, this is no longer true in higher-dimensional Euclidean spaces.
- Except when otherwise specified, this article discusses triangles in Euclidean geometry, namely the Euclidean plane.
given that
let the height of the triangle be x
then the width is x-3
Area = 
54 = x(x -3)

x = 9
height = 9 cm
width = 6cm
Therefore, the height of a triangle is 9 cm.
To learn more about the triangle with the given link brainly.com/question/11897796
#SPJ4
Answer:
Streamers are $2.50 each
Balloons are $1.50 each
Step-by-step explanation:
Make a system of equations
3s + 15b = 30
2s + 4b = 11
Solve by elimination: multiply the top equation by 2 and the bottom equation by -3.
6s + 30b = 60
-6s -12b = -33
18b = 27
b = 1.5
Plug in 1.5 as b to find s
3s + 15(1.5) = 30
3s +22.5 = 30
3s = 7.5
s = 2.5
The streamers are $2.50 and the balloons are $1.50