Question

Subtract:

(i) −8xy from 7xy
(ii) x² from − 3x²
(iii) (x − y) from (4y − 5x)
(iv) (a² + b² − 2ab) from (a² + b² + 2ab)
(v) (x² − y²) from (2x² − 3y² + 6xy)
(vi) (x − y + 3z) from (2z − x − 3y)

Answer 1

(i) 7xy- (-8xy)
= 7xy+ 8xy
= 15xy

(ii) - 3x² - x²
= -4x<sup>2

(iii) (4y - 5x) - (x- y)
= 4y - 5x - x + y
= 5y - 6x

(iv)</sup> (a² + b² + 2ab) - (a² + b² − 2ab)
= $a^2-a^2+b^2-b^2+2ab+2ab$ (Collecting like terms and adding them)
= 4ab

(v) (2x² − 3y² + 6xy) - (x² − y²)
$$\begin{gathered} 2x^2-x^2-3y^2+y^2+6xy \\ =x^2-2y^2+6xy \end{gathered}$$ (Collecting like terms and adding them)

(vi) (2z -x -3y) - (x - y +3z)
= 2z -3z -x -x -3y +y (Collecting like terms and adding them)
= -z -2x - 2y