Question

Y

=
y=
 
 
3
x
+
28
3x+28
y
=
y=
 
 
−
4
x
−4x

Answer 1

(- 4, 16 )

Explanation:

y = 3x + 28 → (1)

y = - 4x → (2)

substitute y = 3x + 28 into (2)

3x + 28 = - 4x ( add 4x to both sides )

7x + 28 = 0 ( subtract 28 from both sides )

7x = - 28 ( divide both sides by 7 )

x = - 4

substitute x = - 4 into (2)

y = - 4(- 4) = 16

solution is (- 4, 16 )

Answer 2

Replace y = -4x into y = 3x + 28

-4x = 3x + 28

Minus both side by 3x

-7x = 28

x = -4

Recheck : - 4 x (-4) = 3 x (-4) + 28
16 = -12 +28 = 16 (t)