Question 102280This question is from textbook
: trying to help my son...everyone in the house has worked and we get different answers. Please help us to understand! Gets confusing w/all the fractions...
c/2 - d/5 = -4;2c/3 -3d/5 = -7
thank you!
This question is from textbook
Answer by Fombitz(32388)   (Show Source):
You can put this solution on YOUR website! If you don’t like fractions, multiply both equations by a number that is the product of all of the fraction denominators. In the denominators, you have 2,3, and 5. 2*3*5=30, so multiply both equations by 30.
And
Now you’ve got two equations, no fractions :
Use one equation to solve for c in terms of d and then substitute into the other equation and solve. Let’s use equation (1).
 Additive inverse of 15c
Before you go any further and solve for d, you might notice that in equation (2) you need a value for -18d. If I take equation (3) and multiply both sides by 3, I will get -18d on the left hand side.
 Multiply both sides by 3.
Now I can plug this value for (-18d) into equation (2) and solve for c.
 Substitute for (-18d).
 Simplify.
 Additive inverse of -360.
 Simplify.
 Multiplicative inverse of (-25)
Now you can use (1), (2), or (3) and solve for d.
Let’s use (1).
 Substitute the value for c.
 All terms are divisible by 6. Simplify.
 Additive inverse of -15.
Check your answer in your original equation.
 True.
Final answers  and .
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