78
because 5 times 2 equals 10 so then u times 39 times 2 and get 78
#7
d/2 +d/5 + d/3 = 3
(15d + 6d + 10d) / 30 = 3
15d + 6d + 10d = 90
31d = 90
d = 90/31
d = 2 28/31
Answer:
A.
x + y = 28
1.68x + 2.44y = 54.64
Step-by-step explanation:
Let x = paperback books and y = hardback books
x+y =28
We know that paperbacks cost 1.68 and hardback cost 2.44
1.68x + 2.44y = 54.64
We have 2 equations and 2 unknowns
x+y =28
1.68x + 2.44y = 54.64
<span>8x^2 - 2x - 1 = 0
(2x - 1)(4x + 1) = 0
2x - 1 = 0; x = 1/2
4x + 1 = 0;x = -1/4
answer
</span><span>{-1/4, 1/2}</span>
For when x is 4 g will be 80 and f will be 108 for when x is 5, g will be 160 and x will be 110 so option 1 as 160-110 is 50
Hope it helped
