Math,help!!! Eng!!+20!!

a) 開方根4+開方根5 = 開方根9 = 3?......................wrong
√4 + √5 = 2 + √5

b) 5開方根3 = 開方根75......................right
5√3 = √5*5*3 = √75

c)開方根6 / 開方根3 = 2......................wrong
√6 / √3 = √18 / 3 = √2

d) 1/開方根2 =開方根2/2......................right
1 / √2 = √2 / 2

因式分解？
a) (x+2)(x+2) / (x-3)(x+2)
=(x+2) / (x-3)

b) x^2+4x / 2x+8
= x(x+4) / 2(x+4)
= x / 2

iii) For the points(-2,1) and (-4,4), find:
a) the distance between the two points.
√(-2+4)2+(1-4)2 = √4+9 = √13

b) the slope of the line containing the two points.
(4-1) / (-4+2) = (-3 / 2)

c) an equation of the line containing the two points.
(y-1) / (x+2) = (1-4) / (-2+4)
so .. 3x + 2y + 4 = 0



1.find the slope of the line containing the points (-1,3) and (4,6).
(6-3) / (4+1) = 3 / 5

2.find the distance between the points (-1,3) and (4,6)
√(-1-4)2+(3-6)2 = √34

3.findanother point on the line containing the points(-1,3)and(4,6) that hasinteger coordinates. Write the coordinates of the point you found.
You have to find an equation of the line containing the two points
(y-3) / (x+1) = (3-6) / (-1-4).......so the equation of the line is...
3x - 5y + 18 = 0
To take any numbers for the equation and to find another point
of integer..........such like......(-6，0)

4.Write an equation for the line containing the points(-1,3) and (4,6).
Answer is like the third subject !