Answer:
x = -7
Step-by-step explanation:
5-x=12
To solve for x, you must first make the equation equal to x (to make x alone on one side).
5 - x = 12
-5 -5
-x = 7
-x(-1)=7(-1)
x = -7
Answer:
1. a + b + c = 180
2. b + d = 180
3. d = a + c
Step-by-step explanation:
1. a + b + c = 180:
Angles in a triangle add up to 180
2. b + d = 180:
Angles in a straight line equal 180 because they are supplementary angles
3. d = a + c:
ΔACD is an exterior angle, and ΔACB is interior adjacent, hence ∠a and ∠c add up to ∠d