Answer:
a. 7
Step-by-step explanation:
7x7=49
 
        
                    
             
        
        
        
Answer:
Shows how to quickly check if a matrix product is defined and, if it is, how to ... You can use this fact to check quickly whether a given multiplication is defined.
Step-by-step explanation:
 
        
             
        
        
        
<u>Let's solve this problem step-by-step</u>
<u>Let's set</u>:
    2x + 6y = 36 -- equation 1
    x + 4y = 20 -- equation 2
(equation 2) * 2
    2x + 8y = 40 -- equation 3
(equation 3) - (equation 1)
    2y = 4
    y = 2 -- equation 4
Plug (equation 4)'s value of y into (equation 2)
    x + 4(2) = 20
    x = 20 - 8
    x = 12 
<u>Thus x = 12 and y = 2</u>
<u>Let's check, by substituting these values</u>
   
<u>Answer: x = 12 and y = 2</u>
Hope that helps!
 
        
             
        
        
        
Answer:
u = (-21)/20
Step-by-step explanation:
Solve for u:
u + 1/4 = (-4)/5
Put each term in u + 1/4 over the common denominator 4: u + 1/4 = (4 u)/4 + 1/4:
(4 u)/4 + 1/4 = -4/5
(4 u)/4 + 1/4 = (4 u + 1)/4:
1/4 (4 u + 1) = -4/5
Multiply both sides of (4 u + 1)/4 = (-4)/5 by 4:
(4 (4 u + 1))/4 = (-4)/5×4
4×(-4)/5 = (4 (-4))/5:
(4 (4 u + 1))/4 = (-4×4)/5
(4 (4 u + 1))/4 = 4/4×(4 u + 1) = 4 u + 1:
4 u + 1 = (-4×4)/5
4 (-4) = -16:
4 u + 1 = (-16)/5
Subtract 1 from both sides:
4 u + (1 - 1) = (-16)/5 - 1
1 - 1 = 0:
4 u = (-16)/5 - 1
Put (-16)/5 - 1 over the common denominator 5. (-16)/5 - 1 = (-16)/5 - 5/5:
4 u = (-16)/5 - 5/5
-16/5 - 5/5 = (-16 - 5)/5:
4 u = (-16 - 5)/5
-16 - 5 = -21:
4 u = (-21)/5
Divide both sides by 4:
u = ((-21)/4)/5
5×4 = 20:
Answer:  u = (-21)/20
 
        
             
        
        
        
6 Square root of 5? Are you sure you didn't type that incorrectly?