Write an equation of each line in standard form with integer coefficients. y=4.2x+1.8

  -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