Andy and Sylvie each incorrectly simplified the expression - 3 - 4 (2x - 3). Andy wrote - 14x + 21 and Sylvie wrote - 8 - 6. Explain their errors and give the correct answer.

Given the expression - 3 - 4 (2x - 3) the correct solution is - 8x + 9.

Step-by-step explanation:

Andy wrote - 14x + 21, so his error was to do de substraction (-3 - 4) and then distribute - 7 (2x-3) = - 14x + 21.

Sylvie wrote - 8x - 6. Her error was to multiplied - 4 only for 2x,

then - 3 - 4 (2x - 3) = - 3 - 8x - 3 = - 8x - 6.