You sure seem to be asking a lot of questions lately. I'd like to see that you've been trying with these problems at least because if you can't get that first one it's almost like you missed the whole lesson.
1. 20 = 4b + 7 + 5
Add the 7 and 5.
20 = 4b + 12
Subtract 12 from each side.
8 = 4b
Divide each side by 4.
2 = b
2. 7 = 6k - 7k
6k - 7k = -1k. (the k acts as a sort of unit)
7 = -1k
Divide each side by -1.
-7 = k
3. 3.23 - 2m = 3 - 2(5m - 2)
Distribute the ×-2 to each term inside the parentheses.
3.23 - 2m = 3 - 10m + 4
Add the 3 and 4.
3.23 - 2m = 7 - 10m
Add 10m to each side.
3.23 + 8m = 7
Subtract 3.23 from each side.
8m = 3.77
Divide by 8.
m = 0.47125
4. -88/45=1/3r+2/5r
To get rid of the fractions, let's multiply everything by 45.
-88 = 15 + 18r
Subtract 15 from each side.
-103 = 18r
Divide by 18.
-103/18 = r
As a mixed number, r = -5 and 13/18
As a decimal, r = -5.7222...
You know that the two angles make up a perfectly flat line, which is a 180<span>° angle. So we can create the equation:'
3x + 10 = 12x
Now solve for 'x'. Subtract 3x to both sides:
10 = 9x
Divide 9 to both sides:
x = 10/9
We want to find the smaller angle, so put this value in for 'x' in '3x + 10':
3x + 10
3(10/9) + 10
30/9 + 10
13 1/3</span><span>°</span>
Answer:
x=5, y=-2. (5, -2).
Step-by-step explanation:
2x+3y=4
3x+4y=7
----------------
3(2x+3y)=3(4)
-2(3x+4y)=-2(7)
----------------------
6x+9y=12
-6x-8y=-14
-----------------
y=-2
2x+3(-2)=4
2x-6=4
2x=4+6
2x=10
x=10/2
x=5
Answer:
$6000
Step-by-step explanation:
accumulated amount = A = PI
A = $6900
Let P = x
6900 - I = x
I = (x)(0.05)(3yrs) = 0.15x
6900 - 0.15x = x
Add
6900 = 1.15x
Divide, solve for x
x = 6000
Answer:
a. 90
b. 360
Step-by-step explanation:
The time taken by humming bird to flap its wings= 0.08 sec
by flying 7.2 seconds a typical giant hummingbird flap its wings 
times
= 90 times
Since, A ruby-throated hummingbird can flap its wings 4 times faster than a giant hummingbird, it will flap its wings in every 0.02 sec
so in 7.2 seconds it will flap 
times = 360 times
