jumlahkanlah dalam bentuk aljabar a)21x + 4y dengan -4x + 7y b)-8a - b dan 11a + 2b c)4a + 7b dengan -11a +15b d) -17x + 10y dengan 15x - 23y

a) (21x + 4y) + (-4x + 7y)
= 21x - 4x + 4y + 7y
= 17x + 11y

b) (-8a - b) + (11a + 2b)
= - 8a + 11a - b + 2b
= 3a + b

c) (4a + 7b) + (-11a + 15b)
= 4a - 11a + 7b + 15b
= - 7a + 22b

d) (-17x + 10y) + (15x - 23y)
= - 17x + 15x + 10y - 23y
= - 2x - 13y

a)(21x+4y)(-4x)+7y)
=21x+4y+-4x+7y
=21x+-4x+4y+7y
=17x+11y

b)((-8a)-b)(11a+2b)
=-8a-b+11a+2b
=-8a+11a-b+2b
=19a-2

c)(4a+7b)(-11a+2b)
=4a+7b+-11a+2b
=4a+-11a+7b+2b
=-7a-9b

d)(-17x+10y)(15x-23y)
=-17x+10y+15x-23y
=-17x+15x+10y-23y
=32x+-13y
=32x-13y