That is Proof by Contradiction.
The famous one is the proof of the square root of 2 is irrational . First done by Euclid
x = a number
7 + 2x = 21
Subtract 7 from both sides
2x = 14
Divide both sides by 2
x = 7
7 is the only number that makes this sentence true.
Answer: a. 10 and 12
explanation:
X/-6 = 11
X = 11 x -6
X = -66
Answer:
-2
Step-by-step explanation:
[3-(-1)]/[2-4] = -2