The acceleration of the bookshelf is equal to 1.30 
<u>Given the following data:</u>
- Mass of bookshelf = 51.5 kilogram
To determine the acceleration of the bookshelf, we would apply Newton's Second Law of Motion:
Newton's Second Law of Motion states that the acceleration of an object is directly proportional to the net force acting on the object while being inversely proportional to its mass.
Mathematically, Newton's Second Law of Motion is given by this formula;

Substituting the given parameters into the formula, we have;

Acceleration = 1.30 
Read more on net force here: brainly.com/question/1121817
First, let's find the slope of the line from the points given.
m = (4 - - 2) / (3 - 1)
m = 6 / 2
m = 3
Secondly, we know that a line perpendicular to the original must have a slope that is the opposite reciprocal of the original. For the given points, the opposite reciprocal slope would be -1/3.
Now, we can put all of the equations below into slope intercept form and find the ones that have a slope of -1/3.
Equation 1: Correct
y = -1/3x - 5
Equation 2: Incorrect
y = 3x - 3
Equation 3: Incorrect
y - 2 = 3(x + 1)
y - 2 = 3x + 1
y = 3x + 2
Equation 4: Correct
x + 3y = 9
3y = -x + 9
y = -1/3x + 3
Equation 5: Incorrect
3x + y = -5
y = -3x - 5
Hope this helps!! :)
Divide, the first operation is the parentheses and then division
-2,-7 because you go the same ammount in the opposite direction
Answer: b is the answer
Step-by-step explanation:
2400-1200=1200