Answer:
35
Step-by-step explanation:
Here we see 5 black keys for every 7 white keys.
So the ratio is 5:7
If we need 49 white keys, find the amount we scale the original ratio by:
49/7 = 7
So we are scaling by a factor of 7.
The number of black keys would be 5 * the scale of 7. = 35
So there should be 35 black keys.
Answer:
A. (-5, 0) and (1, -3)
B. Slope (m) = -½
C. y + 3 = -½(x - 1)
D. y = -½x - ⁵/2
E. ½x + y = ⁵/2
Step-by-step explanation:
A. Two points on the line from the graph are: (-5, 0) and (1, -3)
B. The slope can be calculated using two points,(-5, 0) and (1, -3):

Slope (m) = -½
C. Equation in point-slope form is represented as y - b = m(x - a). Where,
(a, b) = any point on the graph.
m = slope.
Substitute (a, b) = (1, -3), and m = -½ into the point-slope equation, y - b = m(x - a).
Thus:
y - (-3) = -½(x - 1)
y + 3 = -½(x - 1)
D. Equation in slope-intercept form, can be written as y = mx + b.
Thus, using the equation in (C), rewrite to get the equation in slope-intercept form.
y + 3 = -½(x - 1)
2(y + 3) = -1(x - 1)
2y + 6 = -x + 1
2y = -x + 1 - 6
2y = -x - 5
y = -x/2 - ⁵/2
y = -½x - ⁵/2
E. Convert the equation in (D) to standard form:
y = -½x - ⁵/2
½x + y = ⁵/2
Answer:
22
Step-by-step explanation:
mean is calculated as
mean = 
Given the mean of 12 numbers is 20 , then
= 20 ( multiply both sides by 12 )
sum = 240
Given the mean of 8 numbers is 25 , then
= 25 ( multiply both sides by 8 )
sum = 200
Total sum of the 20 numbers = 240 + 200 = 440, then mean of 20 numbers is
mean =
= 22