So OA=4
OB=4
Because the straight line y=kx+b intersects the y axis, and the x axis intersects a and b.
Therefore, let a (0 0,4) b (-4,0) generation y=kx+b obtain:
k= 1
b=4
Replace k= 1 b=4 with y=kx+b: y=x+4.
So the analytical formula of the straight line y=kx+b is y=x+4.
28. (1) It is proved that the intersection D makes DH perpendicular to AB and connects GH.
So AHD angle = BHD angle =90 degrees.
Because DE is perpendicular to BC and e.
So the angle bed =90 degrees.
So angle BHD= angle bed =90 degrees.
Because BD bisects the angle ABC
So angle ABD= angle CBD.
Because BD=BD
So triangular BHD and triangular bed congruence (AAS)
So BH=BE
Because angle ABD= angle CBD
Blood sugar = blood sugar
So triangle BHG and triangle Berg are congruent (SAS).
So angle BGH= angle BGE.
Because AG is perpendicular to BD and g.
So AGD angle =90 degrees
So AHD angle +AGD angle = 180 degrees.
So a, h, d and g are four-point circles.
So angle BAD= angle BGH
So Angel Budd = Angel ·BGE
So a, b, f and g are four-point circles.
So angle ABD= angle AFG
So angle CBD= angle AFG
Because angle AFG+ angle DFE= 180 degrees.
So angle DFE+ angle CBD= 180 degrees.
(2) Solution: Because BD bisects the angle ABC.
So angle ABD= angle CBD= 1/2 angle ABC.
Because the angle ABC=90 degrees
So the angle ABD= the angle CBD=45 degrees.
Because AG is perpendicular to BD and g.
So AGB angle =90 degrees
Because the angle ABD+ the angle AGB+ the angle package = 180 degrees.
So angle ABG= angle ABD=45 degrees.
So AG=BG
From Pythagorean Theorem:
AB^2=AG^2+BG^2
AB= root number 2*BG
Because CG is perpendicular to BC
So the angle BCG=90 degrees
Because angle BCG+ angle CBD+ angle BGC= 180 degrees.
So the angle CBD= the angle BGC=45 degrees.
So BC=GC
From Pythagorean Theorem:
BG^2=BC^2+GC^2
BG= root number 2*BC
So AB/BC=2
Because virtue is vertical BC.
So angle bed = angle DCE=90 degrees.
So angle ABC+ angle bed = 180 degrees.
So parallel AB
So DE/CE=AB/BC
So DE/CE=2
CE= 1/2DE
In the right triangle DEC, it is obtained by Pythagorean theorem:
CD^2=DE^2+CE^2
So CD= root number 5*CE
Because angle DEB= angle BCG=90 degrees
So DE parallel CG
So DE/CG=BE/BC=ME/HC=BE/CE.
Angle FDM= Angle FCH
Angle FMD= Angle FHC
So the triangle DFM is similar to the triangle CFH (AA)
So DM/CH=DF/CF
Because angle DFE= angle CFG
Angle FDM= Angle FCH
So triangle DEF is similar to triangle CGF (AA)
So DE/CG=DF/CF
So DM/CH=EM/CH.
So DM=ME= 1/2DE.
So DM=CE
So CD= root number 5*DM