If 2x-1=13, evaluate the expression -x^2-4x.

-77

Step-by-step explanation:

2x-1=13

2x=13+1=14

x=14/2=7

- 77

Step-by-step explanation:

The given expression is -x^2-4x; there is another expression (2x - 1 = 13), which can be solved for x as follows:

2x - 1 = 13  

Adding 1 to both sides, we get:  

2x = 14

Dividing both sides by 2 results in:  x = 7

Substituting 7 for x in   -x^2-4x   yields   -(7)^2-4(7), or:

-49 - 28, or -77

-3

step-by-step explanation:

a drawing really does here:

so i draw the horizontal line y=2 and the vertical line x=-2 at this intersection i put b (this is where my right angle is going to be).   so point b is at (-2,2).   point a is 5 units long and is also on y=2 so this point has to be (3,2) or (-7,2) -doesn't matter i will go with (3,2).

now we know c is at (-2,y) we don't know the y yet bet we know that c is on x=-2.

we have the area of the triangle is .5bh=12.5

we know the base length is 5 (ab)

we have the height is (2-y) if you look at your

plug in

.5(5)(2-y)=12.5

solve for y to get the y-coordinate for c

2.5(2-y)=12.5

divide both sides by 2.5 giving:

2-y=5

now subtract 2 on both sides

-y=3

y=-3