Using a calculator, you should find these approximations

Solution-
We can solve this problem by using the concept of slope.
Slope of a line joining two points A (x1,y1) and B (x2,y2) is given by-
slope of AB= (y2-y1)÷(x2-x1)
We have given the vertices of a triangle as D(-4,1), E(3,-1) and F(-1,-4).
∴ slope of line joining D and E= (-1-1)÷(3-(-4))= -2/7
slope of line joining D and F= (-4-1)÷(-1-(-4))= -5/3
and slope of line joining E and F= (-4-(-1))÷(-1-3)= 3/4
∵ Two lines are perpendicular to each other if product of their slopes= -1
Statement 1 is wrong because, (slope of DE)×(slope of EF)=(-2/7)×(3/4)=-3/14≠ -1
Statement 2 is wrong because, (slope of DE)×(slope of DF)=(-2/7)×(-5/3) =10/21≠ -1
Statement 3 is wrong because,(slope of DF)×(slope of EF)=(-5/3)×(3/4)= -5/4≠ -1
∴Statement 4 is correct.
Answer:

Step-by-step explanation:
(Interpreting equation as)

We can reduce the fraction by dividing the top and the bottom by terms they have in common.
First, lets rewrite both the numerator and denominator in terms of each other.

If you expand the fraction, you will get exactly what you start with, now this is fine.
As we can see both halves of the fraction have a common term (
), so we can divide by this - and the fraction will still be equivalent to as it was before
, or simplified further,
