Answer: -21x + 5y = 9
Step-by-step explanation:
The standard form says that Ax + By=C
So to covert y = 4.2x + 1.8 into subtract 4.2 from both sides.
y = 4.2x + 1.8
-4.2x -4.2x
-4.2x + 1y = 1.8 Now it is written in standard form and to make the decimals integers we will multiply both sides by 10.
-4.2x(10) + 1y(10) = 1.8(10)
-42x + 10y = 18 which reduces to -21x + 5y = 9