Answer:
centre = (4, 0 ), radius = 5
Step-by-step explanation:
The equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k) are the coordinates of the centre and r is the radius
(x - 4)² + y² = 25 ← is in standard form
with (h, k) = (4, 0) and r = = 5
Thus centre = (4, 0) and radius = 5
Answer:
It states that time spent on social networking sites & twitter have a strong positive correlation.
Step-by-step explanation:
Correlation is the statistical measure of co-movement relationship between two variables. Correlation Coefficient 'r' lies between -1 & +1
Correlation can be following on basis of variables relationship direction
- Positive Correlation : It means two variables move in the same direction - one variable increase, other variable increase & one variable decrease, other variable decrease. 'r' is positive.
- Negative Correlation : It means two variables move in opposite direction - one variable increase, other variable decrease & one variable decrease, other variable increase. 'r' is negative.
Correlation can be following on the basis of variables :
- Strong Correlation : It means the variables fluctuations are more inter-related. r > 0.5
- Weak Correlation : It means the variables fluctuations are less inter-related. r < 0.5
Correlation between times spent on social networking sites & twitter is 0.8 This r = 0.8 means that the two activities have strong positive correlation. It implies that increase in one lead to increase in other activity & vice versa, by a high magnitude.
Answer: £214
Step-by-step explanation:
She works 18 hours in total for week days.
So, 8 x 15 = £120
And, 3 x 10 = £30 for extra hours
120 + 30 = £150
On Saturday she works 4 hours.
8 x 2 = 16 per hour as it doubles
So, 16 x 4 = £64
Finally, £150 + £64 = £214
£214 for last week
Answer:
x=2 true solution
x=-3 extraneous
Step-by-step explanation:
sqrt(x+7) -1 = x
Add 1 to each side
sqrt(x+7) -1+1 = x+1
sqrt(x+7) = x+1
Square each side
(sqrt(x+7))^2 = (x+1)^2
x+7 = x^2 +2x+1
Subtract x from each side
7 = x^2 +x +1
Subtract 7 from each side
0 = x^2 +x - 6
Factor
0 = (x+3)(x-2)
Using the zero product property
x+3 = 0 x-2 =0
x=-3 x=2
Check solutions
x=-3
sqrt(-3+7) -1 = -3
sqrt(4) -1 = -3
3 =-3 extraneous
x=2
sqrt(2+7) -1 = 2
sqrt(9) -1 = 2
3 -1 =2
2 =2 true
Let's think about what happens when you find the price after tax. Let the price before tax be
. The tax rate is
, so the tax part of the total price is
. Adding that onto the original price, we see that
So, we can just divide each side by
to get the original price, which rounded to two decimal places is
.