(I) [tex]3x + 2y = 45[/tex]
(II) [tex]4x - y = 5[/tex]
Get [tex]y[/tex] alone in equation (II)
[tex]4x - y = 5\\y = 4x - 5[/tex]
Insert new equation (II) in equation (I)
[tex]3x + 2(4x - 5) = 45\\3x + 8x - 10 = 45\\3x + 8x = 45 + 10\\11x = 55\\x = 5[/tex]
Insert [tex]x = 5[/tex] in equation (II)
[tex]y = 4 \cdot 5 - 5\\y = 20 - 5\\y = 15[/tex]
