Q

# From the sum of 4 + 3x

Q. 6.    (b) From the sum of $4+3x$ and $5-4x+2x^{2},$subtract the sum of $3x^{2}-5x$ and $-x^{2}+2x+5$.

$\\( 4 + 3x + ( 5 - 4x + 2x^2) ) - ( 3x^2 - 5x + ( -x^2 + 2x + 5) \\= (4 + 3x + 5 - 4x + 2x^2 ) - ( 3x^2 - 5x -x2 + 2x + 5) \\= 4 + 3x + 5 - 4x + 2x^2 - 3x^2 + 5x + x^2 - 2x - 5 \\=4 + 5 - 5 + ( 3 - 4 + 5 - 2 )x + ( 2 - 3 + 1 )x^2 \\=4 + 2x$
On subtracting the sum of $3x^{2}-5x$ and $-x^{2}+2x+5$ from the sum of  $4+3x$ and $5-4x+2x^{2}$ we get $4+2x$