9514 1404 393
Answer:
19. wrong multiplier was used, and used incorrectly; x = -324
20. wrong multiplier was used, and used incorrectly; y = 5
Explanation:
In each case, the equation was multiplied by the coefficient of the variable, instead of divided. In each case, the square of the coefficient was evaluated incorrectly (so the error wasn't noticed).
__
19) As described above.
(-36)(9) = (x/9)(9)
-324 = x
__
20) In addition to the errors described above, the variable was changed from y to x.
15/3 = (3y)/3
5 = y