Inverse operations
What does an inverse operation do?
Undoes/reverses what was done by a previous operation.
To squash fractions you should...
multiply everything by the common denominator.
2(x + 1) = 7
x = 2.5
A number divided by 4 is -7.
n = -28
After solving the equations x + 15 = 21, you find that the value of x is 6. How should you check if your answer is correct?
Plug 6 in for x in your original equation.
What is the inverse operation of addition?
Subtraction
One-third K is 3. What is K?
3(2x + 7) = 14
x = -7/6
Three, plus a number divided by 5 is 6.
n = 15
After solving for x in a linear equation problem you determine that x = 2. You decide you should check your work by plugging your answer of 2 into the original equation for x. However, when you work through the problem, you come up with 7 = 9. What does this mean?
The solution is not correct.
What is the inverse operation of multiplication?
Division
Solve for x.
x/7 + 1/3 = 1
x = 14/3 or 4.66
7.6 = -2(-3 - y)
y = 0.8
One-half of a number is 2.5
n = 5
You are told that an equilateral triangle has a perimeter of 9cm. You need to find the length of each side. Set up an equation which would all you to solve this problem. Use s to represent side length.
9 = 3s
What inverse operation do you need to use to solve 15x = 3?
Solve for r.
1/4 + r = 3r - 4
r = 19/8 or 2.375
6.4 - 9.3b = 25.3 - 3.9b
b = -3.5
A number divided by three, subtract 13.5 is 2.8
n = 48.9
While working out a problem you get an answer of -x = 5. What can you do to make your variable positive?
Multiply everything by -1.
To solve 3x + 1 = 4, what two in inverse operations do you need to use? And in what order?
Subtraction then division.
Solve for w.
17/385 + 42w - 15/2 = -w
w = 5741/33110 or 0.17339
15(z + 25) = 3z + z + 1
z = -34
n = 210/13
4(3 + 3y) = 4y(2) + 3y - 4
12 + 12y = 8y + 3y - 4 [multiplying]
12 + 12y = 11y - 4 [combining like terms]
y = -16