Answer:
x=26
Step-by-step explanation:
The sum of the angles of a triangle add to 180 degrees
(2x-5)° +(4x-1)° + 30° = 180
Combine like terms
6x +24 =180
Subtract 24 from each side
6x+24-24 =180-24
6x = 156
Divide by 6
6x/6 =156/6
x =26
Your answer would be the third and fourth one.
In the third one, you flip the shape over the X axis, and then flip it over X=5.
In the fourth one, you rotate it 180 degrees, around the point (5, 0).
Both would give you DBE.
For #6 I think it's 90+90+90*1/2.
You'll need to know the length of at least one side of the triangle.
You can then use the Sine and / or the Cosine rule.
The first one is a square I’m like 99% sure