Question

Subtract by horizontal method : $(2\mathrm{a}+3\mathrm{b})$from $(5\mathrm{a}-7\mathrm{b})$

Answer 1

To subtract an algebraic expression form another , add the negative of the first expression to the second . In other words , change the sign of each of the terms of the first expression and proceed as you would in the case of addition.

$$\begin{gathered} =(5\mathrm{a}-7\mathrm{b})-(2\mathrm{a}+3\mathrm{b}) \\ =(5\mathrm{a}-7\mathrm{b})+(-2\mathrm{a}-3\mathrm{b}) \\ =5\mathrm{a}-7\mathrm{b}-2\mathrm{a}-3\mathrm{b} \\ =5\mathrm{a}-2\mathrm{a}-7\mathrm{b}-3\mathrm{b} \\ =3\mathrm{a}-10\mathrm{b} \end{gathered}$$

Hence $3\mathrm{a}-10\mathrm{b}$is the difference between the given algebraic expressions