Find an equation of the line which is to the given line the
Find an equation of the line which is to the given line the line through (-2,3) with the y-intercept 2.
Solution
16. Point( -2 , 3) with y intercept 2 --( 0, 2)
Slope m = (2-3)/( 0- (-2)) = - 1/2
Slope of the line perpendicular to the above line , slope = 2
Std slope intercept equation of line: y = mx +c
y = 2x + c . We have one point ( -2 , 3)
3 = -4 +c ----> c =7
y = 2x +7 ( Solution)
17. 27x^4 + 21x^2 + 4 =0
Let y = x^2:
27y^2 +21y +4 =0
Solve by factorisation: 27y^2 + 12y +9y +4 =0
27y^2 +12y +9y +4 =0
3y (9y +4) +1(9y +4) =0
(3y +1)(9y +4) =0
3y+1 =0 ---> y =-1/3
x^2 = -1/3 ---> x =+ /- i/sqrt3
9y +4 =0 ---> y = -4/9
x^2 = -4/9 ----> x= +/- 2i/3
Solution : x= i/sqrt3 , -i/sqrt3 , 2i/3, -2i/3
