Answer: 24.5
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Step-by-step explanation:
It might help to draw it out. See the diagram below.
The base is JK which is 7 units long. I'm picking this as the base because this segment is completely horizontal.
Notice how the base JK spans from x = -3 to x = 4, which we can use subtraction and absolute value to get |J-K| = |-3-4| = 7.
The height is always perpendicular to the base. If the base is JK = 7, then the height is the vertical distance from K (or J) to L. This vertical distance is also 7 units. Subtract the y coordinates and apply absolute value. The base and height aren't always the same number.
Now we can find the area of the triangle
area = base*height/2
area = 7*7/2
area = 49/2
area = 24.5 square units