Question

y-2x=7 and 4y+x=1 solve by substitution

Answer 1

y - 2x=7
y=2x + 7
put this in 4y + x=1
=4(2x+7) + x=1
=8x+ 28+x=1
9x= -27
x = -3
so y=2x+7
y=2(-3)+7
y=1.

Answer 2

i) y-2x = 7. And. ii) 4y+x = 1

i) y=7+2x

Now replacing y by its value in (ii)

4(7+2x)+x = 1

28+8x+x = 1

28+9x = 1

9x = 1-28

9x = -27

x = $\dfrac {-27}{9}$

$\boxed {x = -3}$

Now y will be ;

4y + (-3) = 1

4y-3=1

4y=4

$\boxed {y=1}$