Answer:
Number 4: Using Pythagoras Theorem, 

Number 5:

3:
 It is a right triangle
 It is a right triangle
4:
 Not a right triangle
 Not a right triangle
For the last one:

Rounded down (because the answer needs to be a whole number) is 21
 
        
             
        
        
        
Answer:
answer : B
Step-by-step explanation:
( x + 7) (3x -2) = 3x² - 2x +21x -14
( x + 7) (3x -2) = 3x²+19x -14
 
        
             
        
        
        
Answer:
The estimated sum is ≈10
Step-by-step explanation:
This depends on how your professor wants you to estimate sums. Logically, though, a value of nearly 4 and a value of just over 6 add to about 10. The exact answer would be a bit over 10, at ≈10.14117
 
        
                    
             
        
        
        
(1,-1) and (3,5)
Find slope first
y=mx+b
slope is also m
b is y-intercept
slope = y2-y1/x2-x1
x1=1
x2=3
y1=-1
y2=5
5-(-1)/(3)-(1)
6/2=3
y=3x+b
use (1,-1) into y=3x+b ( using substitution method)
-1=3(1)+b
-1=3+b
Move 3 to the other side
Sign changes from +3 to -3
-1-3+3-3+b
b=-4
Answer: C.) Y = 3x-4