Answer:
see below
Explanation:
a)5a−6b+7c from 13a−4b+8c
13a−4b+8c -(5a−6b+7c)
Distribute the minus sign
13a−4b+8c -5a+6b-7c
Combine like terms
8a +2b +c
b)2x²−3xy+4y² from 3x²−5xy−6y²
3x²−5xy−6y² - (2x²−3xy+4y²)
Distribute the minus sign
3x²−5xy−6y² - 2x²+3xy-4y²
Combine like terms
x²−2xy−10y²
c)x²+4xy−3y² from 2x²−5xy+y²
2x²−5xy+y² - (x²+4xy−3y²)
Distribute the minus sign
2x²−5xy+y² - x²-4xy+3y²
Combine like terms
x²−9xy+4y²
d)4x³−6x²+8x−9 from 7x³−16x+18
7x³−16x+18 - (4x³−6x²+8x−9)
Distribute the minus sign
7x³−16x+18 - 4x³+6x²-8x+9
Combine like terms
3x³+6x²−24x+27