Answer:
x = 
Step-by-step explanation:
Given
6x =
( divide both sides by 6 )
x =
=
×
=
= 
D bc it needs to have a y intercept of -1
If shapes are congruent, then they are mathematically equal (same dimensions, angles etc.). So just locate where the angle x is on both triangles, it should have a value on or a calculable value on the other. If you provide us with the actual sheet I could walk you through it.
If you're struggling with graphing problems, I'd highly recommend that you check out Desmos and Mathaway. All you have to do is type the equations and it graphs it for you. Here's the first question:
(y -3)^2 = 4y - 12
Expand.
(y-3)(y -3) = 4y - 12
y² - 6y + 9 = 4y - 12
y² - 6y -4y + 9 + 12 = 0
y² - 10y + 21 = 0
Factors are -7y and - 3y
y² - 10y + 21 = 0
y² - 3y - 7y + 21 = 0
y(y - 3) -7(y - 3) = 0
(y - 3)(y - 7) = 0
y-3 = 0 or y - 7 = 0
y = 0 + 3 or y = 0 + 7
y = 3 or 7