4.2x - 1.4y = 2.1
-1.4y = -4.2x + 2.1
y = (-4.2/-1.4)x + 2.1/-1.4
y = 3x - 1.5 <==
Answer:
m= 15
Step-by-step explanation:

To solve for m, start by moving the constants (numbers that are not attached to any variable) to the other side of the equation.

Simplify:

Multiply both sides by 9:

Crossing out 3 from the denominator and from 9:
m= 5(3)
m= 15