6x + 8y=12
y = 2x + 18

Your question says

6x + 8y = 12 Equation 1

y = 2x + 18 Equation 2

Now substitute y in place of 2x + 18 in equation 1

So we have;

6x + 8 ( 2x + 18 ) = 12

Using BODMAS, solve for bracket.

6x + 16x + 144 = 12

22x + 144 = 12

Carry 144 to the LHS then the sign will change from + to – that will be,

22x = 12 – 144

22x = –132

Divide both side by 22

x = – 6

Now substitute – 6 for x in equation 2

y = 2 ( – 6 ) + 18

y = – 12 + 18

y = 6

So therefore

x = – 6 and y = 6.

b

step-by-step explanation:

b