bayangan garis dengan persamaan y=-3x +1 diputar dengan R[0;90°],Kemudian di cerminkan terhadap sumbu x adalah

jawab

y = - 3x + 1
T1 → R [O, 90] 
T2 → R(sumbu x)

[tex] \left[\begin{array}{ccc}x'\\y'\end{array}\right]\,=\,T_{2}\,o\,T_{1}\, \left[\begin{array}{ccc}x\\y\end{array}\right] [/tex]

[tex]\left[\begin{array}{ccc}x'\\y'\end{array}\right]\,=\, \left[\begin{array}{ccc}1&0\\0&-1\end{array}\right] \left[\begin{array}{ccc}0&-1\\1&0\end{array}\right] \left[\begin{array}{ccc}x\\y\end{array}\right][/tex]

[tex]\left[\begin{array}{ccc}x'\\y'\end{array}\right]\,=\, \left[\begin{array}{ccc}-y\\-x\end{array}\right][/tex]

x' = -y → y = - x'
y' = -x → x = - y'

subsitusi  ke y = - 3x + 1
(- x' ) = -3(-y' ) + 1
-x = 3y + 1
3y = -x - 1
x + 3y = -1
 atau
x + 3y + 1= 0