Answer:
see explanation
Step-by-step explanation:
(a)
[tex]\frac{3}{7}[/tex] a × - [tex]\frac{21}{15}[/tex] b ( cancel 3 and 15 and 7 and 21 )
= a × - [tex]\frac{3}{5}[/tex] b
= - [tex]\frac{3}{5}[/tex] ab
(b)
3xy(5x²y² - 4yz) ← multiply each term in the parenthesis by 3xy
= 15x³y³ - 12xy²z
