The correct expression is (a) n = 100; (x + 10)^2
<h3>How to determine the value of n?</h3>
The expression is given as:
x^2 + 20x + n
Take the coefficient of x
k = 20
Divide by 2
k/2= 10
Square both sides
(k/2)^2 = 100
The above value represents the value of n
i.e.
n = 100
So, we have:
x^2 + 20x + 100
Expand
x^2 + 10x + 10x + 100
Factorize
x(x + 10) + 10(x + 10)
Factor out x + 10
(x + 10)^2
Hence, the correct expression is (a) n = 100; (x + 10)^2
Read more about trinomial at:
brainly.com/question/1538726
#SPJ1
x = 4/5
2/5=1/2x
Step 1: Flip the equation.
1/2x=2/5
Step 2: Multiply both sides by 2.
2*(1/2x)=2*(2/5)x=4/5
The values of x are -22 and -2 and there are not extraneous solutions
<h3>How to solve the equation?</h3>
The equation is given as:
2|x + 7|= x - 8
Expand the absolute bracket
|2x + 14|= x - 8
Remove the absolute bracket
2x + 14 = x - 8 and 2x + 14 = -x + 8
Evaluate the like terms
x = -22 and 3x = -6
This gives
x = -22 and x = -2
Hence, the values of x are -22 and -2 and there are not extraneous solutions
Read more about absolute value expressions at:
brainly.com/question/24368848
#SPJ1
Finding the regression equation, her average speed on the 9th day should be expected to be of 6.92 minutes per mile.
<h3>How to find the equation of linear regression using a calculator?</h3>
To find the equation, we need to insert the points (x,y) in the calculator.
Researching the problem on the internet, the values of x and y are given as follows:
- Values of x: 1, 2, 3, 4, 5, 6.
- Values of y: 8.2, 8.1, 7.5, 7.8, 7.4, 7.5.
Hence, using a calculator, the equation for the average minutes per mile after t days is given by:
V(t) = -0.15143t + 8.28
Hence, for the 9th day, t = 9, hence the estimate is:
V(9) = -0.15143(9) + 8.28 = 6.92 minutes per mile.
More can be learned about regression equations at brainly.com/question/25987747
#SPJ1
