Question

Solve the given system by the substitution method.
3x + y = 8
7x - 4y = 6​

Answer 1

Answer:

${ \tt{y = 8 - 3x}} - - - (i) \\ \\ = > 7x - 4(8 - 3x) = 6 \\ 7x - 32 + 12x = 6 \\ 19x - 32 = 6 \\ 19x = 38 \\ x = 2 \\ \\ = > y = 8 - 3(2) \\ y = 2$

Answer 2

3x+y=8, so
y=8-3x (rearranged)

7x-4y=6
7x-4(8-3x)=6 (substitute the value of y with 8-3x)
7x-32+12x=6
19x=38
x=2

y=8-3(2)
y=2