Answer:
(-13, -4)
Step-by-step explanation:
It is about as easy to try the solutions as it is to find them from scratch.
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However, we can determine which one it is by adding twice the second equation to the first.
(-2a +3b) +2(a -4b) = (14) +2(3)
-5b = 20
b = -4 . . . . . . matches the first choice
You only flip the inequality sign when you multiply or divide both sides by a negative number.
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Problem 1
The inequality sign flip happens because we divided both sides by -8.
The graph will have a closed circle at 4 with shading to the left.
Three solutions are x = 0, x = 1, x = 2. You can pick any three numbers you want as long as they are 4 or smaller.
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Problem 2
The graph will have an open circle at 13/3 = 4&1/3 = 4.333 approx. The shading is to the left. No inequality sign flip happens because we divided both sides by a positive number.
Your choice of three solutions is correct. You can pick anything smaller than 4.3333
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Problem 3
The solution set is any value 3 or larger. Three solutions are x = 5, x = 6 and x = 7.
The graph has a closed circle at 3 on the number line. The shading is to the right.