For the following straight lines on a graph, determine the area of the triangle in square units, enclosed by the X-axis, the Y-axis and the given Line. 1. x + y = 9
2. x-y=1
3. y=3+x
4. y = 4x+2
5. x = 3y-5

i do not know the answer

step-by-step explanation:

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4