Question

Help me please..... please

Answer 1

Answer:

general rule Un=1.8n-21

U100=1.8(100)-21=159

Step-by-step explanation:

a5=a+4d,  a5=-12

a10=a+9d,  a10=-3

-12=a+4d

-3=a+9d subtract the system of equations

-9=-5d solve for d

d=1.8

substitute d into first equation to find a

-12=a+4(1.8)

a=-19.2

un. = a + (n − 1)d

Un=-19.2+(n-1)(1.8)

Un=1.8n-21