(a) 95 = (x+7)*(x-7)
(b) 95 = (x+7)*(x-7)
Expand the brackets:
95 = x² -7x + 7x -49 = x² - 49
Subtract x² from both sides:
95-x² = -49
Subtract 95 from both sides:
-x²=-49-95
-x²= -144
Divide both sides by -1 to get rid of the negative numbers:
-x²/-1=-144/-1
x²=144
Take the square root of 144:
x = ± squareroot of 144
x = 12 or -12
x = 12 because you cannot have a negative age so Trina is 12 years old.
Answer:
E
Step-by-step explanation:
Solution:-
- We are to investigate the confidence interval of 95% for the population mean of walking times from Fretwell Building to the college of education building.
- The survey team took a sample of size n = 24 students and obtained the following results:
Sample mean ( x^ ) = 12.3 mins
Sample standard deviation ( s ) = 3.2 mins
- The sample taken was random and independent. We can assume normality of the sample.
- First we compute the critical value for the statistics.
- The z-distribution is a function of two inputs as follows:
- Significance Level ( α / 2 ) = ( 1 - CI ) / 2 = 0.05/2 = 0.025
Compute: z-critical = z_0.025 = +/- 1.96
- The confidence interval for the population mean ( u ) of walking times is given below:
[ x^ - z-critical*s / √n , x^ + z-critical*s / √n ]
Answer: [ 12.3 - 1.96*3.2 / √24 , 12.3 + 1.96*3.2 / √24 ]
Hi Kristian
a - 3b = 22
a = b - 2
We need to solve a = b -2 for a
First, we need to substitute b - 2 for a in a - 3b = 22
a - 3b = 22
b - 2 - 3b = 22
-2b - 2 = 22
-2b = 22 + 2
-2b = 24
b = 24/-2
b = -12
Now substitute -12 for b in a = b - 2
a = b -2
a= -12 - 2
a= -14
Thus, the solution is a = -14 and b = -12
The correct option is the last one (-14,-12)
If you have questions about my answer, please let me know.
Good luck!
Answer:
Step-by-step explanation:
area = ½bh = 12 mm²
bh = 24 mm²
(b,h) = (3,8) and (6,4)
y = sqrt(x) .... parent function
y = sqrt(x+2) .... replace x with x+2 to shift 2 units to the left
y = sqrt(x+2)+3 ... add on 3 to move 3 units up
y = sqrt(-x+2)+3 ... replace x with -x to reflect over y axis
<h3>Answer: y = sqrt(-x+2)+3</h3>
