Answer:
Area = length x width
Area = (3width - 13) x width
Area = 3 width^2 -13width
56 = 3width^2 -13 width
Width = 7
Length = (3 *7) -13 = 8
Step-by-step explanation:

We need to solve for x, we need to get x alone

Lets start by removing -5
Add 5 on both sides


Now to isolate x , we need to remove the square from x
To remove square , take square root on both sides

square and square root will get cancelled

So
and 
To know what kind of triangle is it. use the pythagorean theorem:
A^2 + B^2 = C^2,
where C is the longest side of the triangle
if it satisfies the equation then it is a right triangle
if it does not then A^2 + B^2 > C^2 so it is acute triangle
if A^2 + B^2 < C^2 it is obtuse triangle
18^2 + 13^2 ? 27^2
324 + 169 ? 729
493 < 729 so it is obtuse triangle
X-9=12
x-9+9=12+9
You need to add 9 to each side of the equation.
x=21
Answer:
9/4, 3/2, 1, 7/8, 5/8
Step-by-step explanation: