What does Sam need to score on the fourth test to ensure that she will have an average of 90% for all four tests?
1 answer:
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Let's solve the first inequality at first. So,
−2(x + 4) + 10 < x − 7
-2x- 8 + 10 < x - 7 By distribution property.
-2x + 2 < x - 7 Adding the like terms.
-2x < x - 7 - 2 Subtract 2 from each sides.
-2x < x - 9 By simplifying.
-2x - x < -9 Subtract x from each sides.
-3x < -9
Since we are dividing by negative 3. So, sign of inequality will get change.
So, x>3
Now the next inequality is,
−2x + 9 > 3(x + 8)
-2x + 9 > 3x + 24
-2x > 3x + 24 - 9
-2x > 3x + 15
-2x - 3x > 15
-5x >15
So, x <-3
Hence, the correct choice is x > 3 or x < −3.