For
(c+d)(ex+f)
the expanded form is
dex^2+dex+cfx+df
(ce)x^2+(de+cf)x+(df)
ax^2+bx+c
the value of a is ce
the value of b is de+cf
the value of c is df
so
(-2x+3)(x+8)
(-2x+3)(1x+8)
b is 3*1+-2*8=3-16=-13
answer is -13
so pick 13 because we have -B, so B=13
Count how long it is in the spaces
Let a, b and c be in a geometric sequence, then ac = b^2
Hence, (2k + 1)(7k + 6) = (3k + 4)^2
14k^2 + 19k + 6 = 9k^2 + 24k + 16
5k^2 - 5k - 10 = 0
5k^2 + 5k - 10k - 10 = 0
5k(k + 1) - 10(k + 1) = 0
(5k - 10)(k + 1) = 0
5k - 10 = 0 or k + 1 = 0
5k = 10 or k = -1
k = 2 or k = -1
The geometric sequence formed is
2(2) + 1, 3(2) + 4, and 7(2) + 6
5, 10, and 20
OR
2(-1) + 1, 3(-1) + 4, and 7(-1) + 6
-1, 1, and -1
X=15-12
X=3(number of days in difference to the number of people)
X=9-3
X=6 it would take 6 days to cut the grass with 9 boys
C because 19x899 equals 17081