3x(3x-2y) 
you have to find a common factor between the two numbers. in this case it's three, so you just divide each number by three.
        
             
        
        
        
Answer:
a = √10
Step-by-step explanation:
a² + b² = c²
a² + 9² = (√91)²
a² + 81 = 91
a² = 10
a = √10
hope this helps :)
 
        
                    
             
        
        
        
Depth of Hank descends = The point he reached - the point where he worked initially
                                           = 57 - 10
                                           = 47 ft
Hence, Hank descends 47 ft.
 
        
             
        
        
        
Answer:
Step-by-step explanation:
1. area of square=10²=100 cm²
area of circle=πr²=π×2.5²=6.25π cm²
reqd. area=100-6.25π ≈80.375 cm²
2.
area of circle=π×2.5²=6.25π≈6.25×3.14≈19.625 cm²
area of rectangle=4×3=12 cm²
reqd. area=19.625-12≈7.625 cm²
3.
area of two circles=2×π×3²=18π≈18×3.14≈56.52 cm²
area of square=12²=144 cm²
reqd. area=144-56.52≈87.48 cm²
4.
area of smaller circle=π×4²=16π cm²
area of bigger circle=π×8²=64π cm²
area of two circles=16π+64π=80π cm²
diameter of bigger circle=4+4+8+8=24 cm
diameter of biggest circle=π×12²=144π
area of shaded region=144π-80π=64π≈200.96 cm²
 
        
             
        
        
        
Enter an image, please then people would understand.