1) an = a1 + d*(n-1) => a20 = -4 + (-9)*19 = -4 - 171 = - 175
1) ---> C)
2) a81 = 20 + 4*80 = 340;
2) ---> A)
3) a12 = ?
3) ---> B) or D).
1/3 of the wall takes 1/2 gallon paint.
3(1/3 wall) takes 3(1/2 paint)
1 wall takes 3/2 paint
Answer: 1
gallons paint
Since x = y + 2
so
y + 2 + 4y = 7
5y + 2 = 7
5y = 7-2
5y = 5
y = 1
x= y + 2
x = (1) + 2
x = 3
(x,y) = (3,1)