38 < 4x + 3 +7 - 3x (original equation)
38 < 4x - 3x + 3 + 7 (combine like terms)
38 < x + 10 (simplify)
38 - 10 < x + 10 - 10 (subtract 10 from both sides to get (x) alone)
28 < x (simplify)
x > 28 (switch to get x on the left (its proper equation writing >.<) )
Answer:
He determined pounds per dollar by dividing 10 by 25 but wrote the unit rate as a dollar value.
Step-by-step explanation:
Given



Required
Determine Ming's error
Ming's error is from here

He calculated the unit rate as pound per dollar.
So, after calculating the unit rate, the unit should be:

But instead, he solved as:

<em>Hence, (a) is correct</em>
There is only 1 real number solution