5y^3 ( -x^4)
When x is -2 and y is -1
5y^3(-x^4)
5(-1)^3(2^4)
5(-1)(16)
-5(16)
-80
Substitute the x and y for the values, and put them in parenthesis. This is crucial: you HAVE to use parenthesis or else the exponents and double negative will get messed up. After that, it is just order of operations. One to the third power is negative one, and negative negative two is just two, which to the fourth power is sixteen. Five times negative one is negative five, and negative five times sixteen is negative eighty.
-1^3 = -1
(--2^4) = -2^4 = -16
5*-1*-16 = 80
To find the value of the expression 5y^3(-x^4) when x is -2 and y is -1, you need to substitute -2 for x and -1 for y in the expression and then evaluate the result.
Step 1: Replace x with -2 and y with -1 in the expression.
5(-1)^3(-(-2)^4)
Step 2: Simplify the expression inside the parentheses first.
5(-1)(-2)^4
Step 3: Evaluate the exponent (-2)^4.
5(-1)(16)
Step 4: Multiply the remaining numbers together.
-80
Therefore, when x is -2 and y is -1, the value of the expression 5y^3(-x^4) is -80.