-y²-3xy if x = -5/6 and y = -12

Substituting x = -5/6 and y = -12 into -y² - 3xy:

-(-12)² - 3(-5/6)(-12)

Simplifying:

-144 - 3(5/6)(-12)

-144 - 3(-10)

-144 + 30

= -114

To find the expression -y² - 3xy when x = -5/6 and y = -12, follow these steps:

Step 1: Substitute the given values for x and y into the expression -y² - 3xy.

Substituting x = -5/6 and y = -12, we have:

-(-12)² - 3(-5/6)(-12)

Step 2: Simplify the expression using the order of operations (PEMDAS/BODMAS).

-(-12)² is equal to -(-12) * (-12) = 12 * 12 = 144

Next, we can simplify -3(-5/6)(-12):

-3 * (-5/6) * (-12) = 15/2 * (-12)

Multiplying fractions: 15/2 * (-12) = -15 * 12 / 2 = -180/2 = -90

Step 3: Substitute the simplified values back into the original expression.

Plugging the simplified values back into the original expression, we have:

-y² - 3xy = 144 - 90

Step 4: Perform the remaining operation to get the final answer.

144 - 90 = 54

Therefore, when x = -5/6 and y = -12, the expression -y² - 3xy is equal to 54.