Answer:
x = 20
Step-by-step explanation:
The sum of the 3 angles in a triangle = 180°
Using ΔAHC , then
∠ACH = 180 - (2x + 100) = 180 - 2x - 100 = 80 - 2x
∠ECD = ∠ACB ( vertical angles are congruent ), thus
∠ECD = ∠ACH + ∠HCB, that is
3x = 80 - 2x + x
3x = 80 - x ( add x to both sides )
4x = 80 ( divide both sides by 4 )
x = 20
Step-by-step explanation:
f(x) = x² - 4
y = x²-4
x = y²-4
x + 4 = y²

The solution to the systems of equations is (7, 3)
Given the systems of equations expressed as:
-x + 4y = 5 ....................1
x - 5y = -2 ...................... 2
Add both equations to have:
-x+x + 4y - 5y = 5 - 2
4y-5y = -3
-y = -3
y = 3
Substitute y = 3 into equation 1:
-x + 4(3) = 5
-x + 12 = 5
-x = 5 - 12
-x = -7
x = 7
Hence the solution to the systems of equations is (7, 3)
Learn more on simultaneous equations here: brainly.com/question/148035