Answer: 100 i think, but am not sure.
Step-by-step explanation:
The formula for area of a rectangle is A=l*w.  Since the area is 84, then you can use the A=l*w formula.  84 = x(x+8) would be the equation to solve for x.
 
Now, you need to put the equation in standard form.  So, x2 + 8x - 84 = 0.
 
Since you can't solve this quadratic using factoring, you need to complete the square.
 
To complete the square you need to add 84 to both sides.  Now you have x2 + 8x = 84.  Take the coefficient for the x term (8) and divide by 2.  Now square it.  That would be 42, so 16.  Now you have x2 +8x +16 = 100.
 
Factor x2 +8x +16, so (x+4)2 = 100
 
If you use the square root property, you have x+4 = 10.  Therefore, x = 6 (the short side) and 14 is the long side.
 
 
        
             
        
        
        
Answer:
Step-by-step explanation:
18/12 = 24/(x-2) Put the similar sides in the propertions.
 
        
             
        
        
        
Answer:
x = 71°
Option B is correct answer.
Step-by-step explanation:
We need to find for what value of x is  , where 0°< x < 90°?
, where 0°< x < 90°?
Solving:

So, we get x = 71°
Option B is correct answer.
 
        
             
        
        
        
Answer:
y=-0.5x+8
Step-by-step explanation:
Opposite reciprocal of 2: -0.5
6=-0.5*4+b
6=-2+b
b=8
 
        
             
        
        
        
Answer:
18) 4 * 10 ^ -10
19) t ^ 9
Step-by-step explanation:
18. When multiplying in scientific notation, just multiply the regular numbers together and add the exponents for the tens.
So it'll be 40 * 10^-11
However, the beginning number should have the decimal right after the 4, not any place after (for example, it's 3.056, not 30.56 or 3056.)
To fix this, move the decimal place forward one space from 40. to 4.0, and add 1 to the -11 power.
So the answer is now 4 * 10^-10
19. When dividing exponents, if the base number is the same, you can divide. (Basically, you can not divide x^2 and y^3 because x and y aren't the same)
Since in this case it's t, you can divide.
Dividing exponents is simple: just subtract them.
14 - 5 = 9
so the answer is t ^ 9