8x-y evaluate the expression when x=2 and y=-4

20

Step-by-step explanation:

We are given the expression with two variables x and y and are asked to evaluate the expression 8x - y. We can complete this task by putting the values of x and y in that expression.

x = 2

y = -4

8x -y

= 8 (2) - (-4) //two negatives become positive

= 16 + 4 = 20

Value of expression when x = 2 and y =-4 is 20

Step-by-step explanation:

The given expression be, 8x - y

when x = 2 and y = -4  means that, substituting the value of x and y in the given expression

To find the value of expression

8x - y (1)

x = 2 and y = -4

substitute the values of x and y in (1)

8x - y = 8*2 - (-4)

= 16 + 4 = 20

Therefore the value of expression when x= 2 and y = -4 is 20

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step-by-step explanation:

step-by-step explanation:

we have

using a graphing tool

see the attached figure

this is a quadratic equation (vertical parabola) open up

the vertex is a > vertex

the domain of the function is all real > interval (-∞,∞)

the range of the function is the > [-6.125,∞)

the function has two x->   and

the function is increasing over the > (0.25,∞)

the function is decreasing over the > (-∞,0.25)