Question 580378
write an equation of a vertical line through (4,3).

x=4

write an equation of the line parallel to the line 8x - 2y = 7 passing through (2,-1).

8    	x		-2	y  	=	7	
Find the slope of this line							
make y the subject							
-2	y  	=	-8    	x	+	7	
Divide by	-2						
	y  	=	4    	x		-3 1/2	
Compare this equation with y=mx+b							
slope m =	4    						
The slope of a line parallel to the above line will be the same							
The slope of the required line will be			4    				
m=	4    	,point	(	2	,	-1	)
Find b by plugging the values of m & the point in							
y=mx+b							
-1	=	8      	+	b			
b=	9						
m=	4    						
Plug value of  the slope  and b					in y = mx +b		
The required equation isy  	=	4    	x	+	9      




find all values of x for which (x,6) is on the graph of f (x) = x2 + 3x -4
6=x^2+3x-5
x^2+3x-10=0
(x+5)(x-2)=0
x=-5 & 2