Answer:
Associative 
you can change (8*5) *10 to (8*10) *5
You can change 8*( 5*10) to 10* (8*5)
 
        
             
        
        
        
Answer:
70.
Step-by-step explanation:
Let x be the required number.
We are asked to find the number whose 90% equals to 63.
We can represent our given information in an equation as:
Now, we need to solve for x.
Therefore, 90% of 70 is 63.
 
        
             
        
        
        
Answer:
x=60
Step-by-step explanation:
I'm assuming you meant this: (x/5)-8=4
In which case you would add 8 to both sides to get rid of the 8 on the left (your goal is to get x by itself so you want to move the numbers on the x side to the other side of the equal sign)
(x/5)=12
Then you would multiply 5 on both sides to get rid of the fraction with the 5 on the bottom on the left side.
x=60
There's your answer.
 
        
             
        
        
        
Solutions
To solve this problem we have to use the Pythagorean theorem. You can only use the Pythagorean theorem in Right Triangles. The longest side of the triangle is called the "hypotenuse". C² is the longest side so it is the hypotenuse . To calculate c² we have to do α² + β² = c². 
Given 
One leg of a right triangular piece of land has a length of 24 yards. They hypotenuse has a length of 74 yards. The other leg has a length of 10x yards.
First leg (24 yards) would be α 
Second leg would be β
Hypotenuse (74 yards) would be c
Now we have points α β c.  
a² (24) + β² ( x ) = c² (74) 
Calculations 
c² = α² + β²
74² = 24²+ β² 
<span>5476 = 576 + </span>β² 
5476 - 576 = β²
<span> </span>
<span>4900 = </span>β² 
→√4900 
<span> </span>
β<span> = 70 yards 
</span>
<span>70 = 10x 
</span>
<span>x = 70</span>÷<span>10 = 7 yards  
</span>
The second leg = 7 yards