Factors of 26 are 1, 2, 13, 26 all you have to do is figure out which numbers can go until a number and in this case the number is 26.
Because it is an isosceles triangle, the two base angles have to be the same, so
36°+36°=72°
angles in all triangles add up to 180°, so
180°-72°=108°
unknown=108°
I'll start 18 and 22 for you, and you should then be able to do the rest on your own!
For 18, what we literally do is apply the distance formula for all the points and add them up. For B to C, we get the distance between them to be
sqrt((x1-x2)^2+(y1-y2)^2)=sqrt((0-4)^2+(3-(-1))^2)=sqrt((-4)^2+4^2)=sqrt(16+16)=sqrt(32). Repeat the process for C to E, E and F, and F to B then add the results up to get your answer!
For 22, since the area of a rectangle is length*width (we know given the right angles and that the opposite sides are equal in how long they are), we can multiply 2 perpendicular lines, for example, BC and CE to get sqrt(32)*sqrt(8)=16 as the area
F(x) = 4x - 9
let f(x) = y, this implies that x = f⁻¹(y)
y = 4x - 9 Let us solve for x.
4x - 9 = y
4x = y + 9
x = (y + 9)/4
Recall that x = f⁻¹(y),
x = (y + 9)/4
f⁻¹(y) = (y + 9)/4
That means that for f⁻¹(x)
f⁻¹(x) = (x + 9)/4
Hope this explains it.