Answer:
31 is a prime number.
How to tell if a number is prime: estimate the square root. In this case, we know the square root of 31 is between 5 and 6 and it isn’t divisible by either of those. If it is divisible by a number higher than it’s square root, the other factor must be lower. Is it divisible by 4 or 2? no, because it isn’t an even number. It’s not divisible by 3, because there’s a remainder of 1 if you try. You’ve eliminated all numbers less than the square root, so it is prime
Answer:
the last one
Step-by-step explanation:
plug in -2 for x and -3 for y
Answer:
2
Step-by-step explanation:
We are asked to perform the subtraction
x² + xy - 3y² - (5x² - xy + y²) ← distribute the parenthesis by - 1
= x² + xy - 3y² - 5x² + xy - y² ← collect like terms
= (x² - 5x²) + (xy + xy) + (- 3y² - y² )
= - 4x² + 2xy - 4y²
