Question

Hi! having an exam soon and kind of confused about this. any help appreciated!

Answer 1

Answer:

(14, 23)

area = 400 square units

Step-by-step explanation:

Part (a)

To find the point where two equations meet (the point of intersection), equal the equations to each other, then solve for x.  Substitute the found value of x into one of the equations (it doesn't matter which) and then solve for y.  (x, y) is the point of intersection.

Equation 1:  y = 2x - 5

Equation 2:  y = 23

Equate the equations:

            y = y

⇒ 2x - 5 = 23

⇒       2x = 23 + 5

⇒       2x = 28

⇒          x = 28 ÷ 2

⇒          x = 14

Usually we'd substitute the found value of x into one of the equations and solve for y, however, as one of the equations is literally the y value, we don't need to do that.

So y = 23

Therefore, the point of intersection is (14, 23)

Part (b)

The vertices of the triangle will be the points where each pair of lines meet each other.  We have already determined that one pair of lines meets at point (14, 23).

y = 2x - 5 is a diagonal line, y = 23 is a horizontal line, and x = -6 is a vertical line.

So x = -6 and y = 23 meet at (-6, 23)

Now we just need to determine where y = 2x - 5  and  x = -6 meet.

Simply substitute x = -6 into y = 2x - 5:

⇒ y = 2(-6) - 5

⇒ y = -17

Therefore, the point of intersection is (-6, -17)

So we have three points of intersection which are the three vertices of the triangle:

(14, 23)  (-6, 23) (-6, -17)

As y = 23 is a horizontal line and x = -6 is a vertical line, their point of intersection (-6, 23) is a right angle.

Therefore the can determine that the height of the triangle is the difference between the y-coordinates of (-6, 23) and (-6, -17).

Similarly, the base (width) of the triangle is the difference between the x-coordinates of (-6, 23) and (14, 23).

Therefore, the height = 23 - -17 = 23 + 17 = 40

Therefore, the base = 14 - -6 = 14 + 6 = 20

Area of a triangle = 1/2 x base x height = 1/2 x 20 x 40 = 400 square units

see attached diagram