Answer:
<em>The area of the triangle DEF is 10.</em>
Step-by-step explanation:
<u>Area of a Triangle:</u>
A triangle of base B and height H (both must be perpendicular) has an area of:

The image below shows the triangle formed by the points DEF. It's important to notice the points E and F lie on the same horizontal line because they both have the same y-coordinate.
This fact simplifies the calculations since we can easily compute the length the of base as the difference of their x-coordinates:
B=3-(-2)=3+2=5
Being the base of a horizontal line, the height of the triangle can be calculated as the difference of y-coordinates of D and the height of that line.
H=2-(-2)=4
With these two values, we calculate the area:

The area of the triangle DEF is 10.
Answer:
The number is -1/2
Step-by-step explanation:
Let x be the number
2x+8 = 7
Subtract 8 from each side
2x+8-8 = 7-8
2x = -1
Divide each side by 2
2x/2 =-1/2
x = -1/2
The number is -1/2
Answer:
A is your answer
Step-by-step explanation:
Substitute -3 to x
(-3)^2 + 4(-3) + 1
9 - 12 + 1
= -2