First you cross multiply.
2*(b-4)=6b
Then distribute the 2.
2b-8=6b
Minus 2b from each side.
-8=4b
Divide each side by 4.
-2=b
So -2 is your answer.
Answer:
729
Step-by-step explanation:
I have not done this in some time so the terms may be a bit unconventional, but they work. The key to this is multiplying by -3.
1*(-3) = -3
-3*(-3) = 9
And so on.
1, -3, 9, -27, 81, -243, 729
A true or false question is a question that gives you a statement, and asks whether it's true (correct) or false (wrong).
The magnification is 0.54
Given,
The distance between object and concave lens, u = -21 cm
Focal length of the concave lens, f = -25 cm
Let m be the magnification.
m = v/u
Here v is the position of image.
We have to find v first.
By using lens equation we can determine v.
That is,
1/f = 1/v – 1/u
So,
- (1/25) = 1/v – (-1/21)
- (1/25) = 1/v + 1/21
1/v = - (1/25) – 1/21
1/v = (-25 – 21) / (21 x 25)
1/v = - (46/525)
Therefore v = - (525/46)
v = -11.41 cm
Now we have to find magnification, m.
m = v/u
= (-11.41) / (-21)
= 0.54
Here magnification is 0.54
Learn more about concave lens here: brainly.com/question/12944945
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