Answer:
Step-by-step explanation:
Given that A is a square matrix and A is idempotent

Consider I-A
i) 
It follows that I-A is also idempotent
ii) Consider the matrix 2A-I

So it follows that 2A-I matrix is its own inverse.
Answer:
Yes, △ABC ∼ △FED by AA postulate.
Step-by-step explanation:
Given:
Two triangles ABC and FED.
m∠A = m∠B
m∠C = m∠A + 30°
m∠E = m∠F = 
m∠D =
°.
Now, let m∠A = m∠B = 
So, m∠C = m∠A + 30° = 
Now, sum of all interior angles of a triangle is 180°. Therefore,
m∠A + m∠B + m∠C = 180

Therefore, m∠A = 50°, m∠B = 50° and m∠C = m∠A + 30° = 50 + 30 = 80°.
Now, consider triangle FED,
m∠D+ m∠E + m∠F = 180

Therefore, m∠F = 50°
m∠E = 50° and
m∠D = 
So, both the triangles have congruent corresponding angle measures.
m∠A = m∠F = 50°
m∠B = m∠E = 50°
m∠C = m∠D = 80°
Therefore, the two triangles are similar by AA postulate.
Answer:

Step-by-step explanation:
Given the system of equations:


In order to find the y coordinate of the solution we must first find the solution to this system of equations. We first start by solving one of the given equations and then substitute the answer of that into the second equation and further solve to get the final answers.




















Hope this helps.
Answer:
The width of the rectangular patio is 8 1/4 feet, or as a decimal, 8.25 feet
Step-by-step explanation:
Answer:
A =112 in^2
Step-by-step explanation:
The area of a parallelogram is found by
A = bh where b is the base length and h is the height
A = 14*8
A =112 in^2