Answer:
The specific latent heat.
X - 6 is th algebraic expession for six lss than a number. x represents the number and you are taking 6 away from it. This is the basis of all algebra
18:10 is and equivalent ratio
bearing in mind that standard form for a linear equation means
• all coefficients must be integers, no fractions
• only the constant on the right-hand-side
• all variables on the left-hand-side, sorted
• "x" must not have a negative coefficient
quick note:
the "x" must not have a negative coefficient for the standard form, though in this case it shows like so in the inappropriate choices above.