Answer:
b
Step-by-step explanation:
the sum of 3 and 7 is 3+7. then times x 
 
        
             
        
        
        
Answer:
21) 12 cm
22) 5.9 cm
Step-by-step explanation:
21) The base is 10, and if the other two sides are congruent and the perimeter is 36, we can figure out with simple algebra that the sides are 13 cm long. 
Half of 10 is 5, so we can use the pythagorean theorem. 
5^2+x^2=13^2
Rearranging the variables we have 169-25=x^2
144=x^2
x can be plus or minus 12, but since negative length is impossible we find that x is positive 12 cm. 
22) We want to use sine, because we have opposite and hypotenuse. A simple and easy way to memorize this is the SohCahToa method. If we have opposite (O) and hypotenuse (H) we have OH. Soh has the letters O and H, and the S means we should use sine. 
sine 36=a/10
Plug this into a calculator or desmos scientific calculator to get a=5.9
 
        
             
        
        
        
First divide both sides by 5. Then you get the answer. -0 or 0 I'm not sure tho 
 
        
                    
             
        
        
        
Let Z be the reading on thermometer. Z follows Standard Normal distribution with mean μ =0 and standard deviation σ=1 
The probability that randomly selected thermometer reads greater than 2.07 is
P(z > 2.07) = 1 -P(z < 2.07)
Using z score table to find probability below z=2.07 
P(Z < 2.07) = 0.9808
P(z > 2.07) = 1- 0.9808 
P(z > 2.07) = 0.0192
The probability that a randomly selected thermometer reads greater than 2.07 is 0.0192 
 
        
             
        
        
        
(3x² -7x⁴) from (5x² - 3x⁸)
= 5x² - 3x⁸ - (3x² -7x<span>⁴ )
= </span> 5x² - 3x⁸ - 3x² + 7x<span>⁴ 
= </span>- 3x⁸ + 7x⁴ +  5x² <span>- </span><span>3x²
</span>
= - 3x<span>⁸ </span>+ 7x⁴ +  2x<span>²</span>