Determine which of the following expressions are in factorised form. Select all the correct options.
$-5\left(2y+z\right)-b\left(2y+z\right)$−5(2y+z)−b(2y+z)
$\left(a+7\right)\left(a+2\right)$(a+7)(a+2)
$\left(x-5\right)\left(x+y\right)$(x−5)(x+y)
$3x\left(a+2b\right)+2\left(a+2b\right)$3x(a+2b)+2(a+2b)
Consider $\left(a+b\right)\left(c+d\right)$(a+b)(c+d) and $ac+ad+bc+bd$ac+ad+bc+bd.
Consider $\left(x+2\right)\left(y-9\right)$(x+2)(y−9) and $xy-9x+2y-18$xy−9x+2y−18.
Consider $\left(8-x\right)\left(7-y\right)$(8−x)(7−y) and $56-8y-7x+xy$56−8y−7x+xy.