Question

Solve for 'x' and 'y', using the method of substitution:
4x + 3y = 12; x - 6y = 9 [3 Marks]

Answer 1

$4x+3y=12$ ___(i)
$x-6y=9$ _____(ii)
From equation (ii),
$x=6y+9$ _____(iii) [1 Mark]
Plug this value in equation (i)

$⟹4(6y+9)+3y=12$
$24y+36+3y=12$
$27y=-24$
$y=-\frac{8}{9}$ [1 Mark]
Plug the value of y in equation (iii): $x=6y+9$

$x=-\frac{48}{9}+9$
$x=\frac{33}{9}$
The solution is $\frac{33}{9},-\frac{8}{9}$ [1 Mark]