Answer:
4.47
Step-by-step explanation:
3x²+31=91
3x²=91-31
3x²=60
x²=60÷3
x²=20
x=√20
x=4.47
Answer:
slope = -2
Step-by-step explanation:
(-5,2) (-8,8)
equation to find slope: 
= 
= 
= -2
Answer: A
(He has the side lengths in the wrong place in the cosine ratio)
Answer:
2 mm
Step-by-step explanation:
Let x be the sides of the original square,
then the area of the original square is x^2
The sides of the new square is x + 6
The area is (x + 6)^2
Then (x + 6)^2 = 16*x^2
Take square root on both sides and get
x + 6 = 4x,
3x = 6
so x = 2 mm
