Question

y = 3x - 87

3x + 2y = 21

solve using the substitution method ....?

Answer 1

Put y = 3x -87 in second eq.
3x +2(3x -87) = 21
find x
then use that value of x to find y

Answer 2

Im confused.. could you explain it a little better?? like in detail..??

Answer 3

in substitution method, substitute one unknown (x) in place of second unknown (y)

you have two equations
y = 3x -87
3x +2y = 21

now use value of y from first eq. in second eq

3x + 2(3x-87) = 21
3x +2*3x - 2*87 = 21
3x+6x - 174 = 21
9x = 174 +21
9x = 195
x =195/9 = 21.6

Now put this value of x in first eq. to find y

Answer 4

thanks

Answer 5

that's not how I did it though..

Answer 6

getting correct answer is important