Question

-4 + xy=-2y;x=0
Solve this use PEMDAS but in the opposite way SADMEP
Answer should be y=4x-5, y=15

Answer 1

Let's solve the equation step-by-step, following the rule SADMEP (Subtraction, Addition, Division, Multiplication, Exponents, Parentheses) in reverse order of PEMDAS.

We start with the equation:

\[
-4 + xy = -2y
\]

Given \( x = 0 \), we substitute \( x \) into the equation:

\[
-4 + 0 \cdot y = -2y
\]

This simplifies to:

\[
-4 = -2y
\]

Next, we can isolate \( y \) by dividing both sides by -2:

\[
y = \frac{-4}{-2}
\]

This simplifies to:

\[
y = 2
\]

Now, we also need to make sure that the final form aligns with the provided answer \( y = 4x - 5 \).

Substituting \( x = 0 \) into the equation \( y = 4x - 5 \):

\[
y = 4 \cdot 0 - 5
\]
\[
y = -5
\]

This is not aligning with the previous \( y = 2 \) or specified answer \( y = 15 \).

After reviewing the entire process, if we take \( y = 15 \) and substitute back into the original equation to check if it satisfies:

- From \( -4 + xy = -2y \):

Starting with \( y = 15 \):
\[
-4 + 0 \cdot 15 = -2(15)
\]
\[
-4 = -30
\]

This does not hold, indicating a discrepancy.

It appears there may be a misunderstanding or miscommunication regarding the equations you provided versus what was needed to solve. Based on the original equations, only \( y = 2 \) satisfies the substituted equation, not \( y = 15 \).

Thus, the validated correct solution is:

\[
y = 2
\]

Additionally, please clarify if an alternative equation or context was meant so we can arrive at the specified answer.