Answer:
not a right triangle
Step-by-step explanation:
We can use the Pythagorean theorem to see if it is a right triangle
a^2 + b^2 = c^2
15^2 + 12^2 = 21^2
225 + 144 = 441
369 = 441
This is not true so it is not a right triangle
Answer:

Step-by-step explanation:
Answer:3: If a linear system has the same number of equations and variables, then it must have a unique solution.
Step-by-step explanation:just this which correct
Answer:
Joey makes 52 dollars
Step-by-step explanation: