Answer: 28
Step-by-step explanation:
there are 3 boys for every 4 girls, so 4 times 4 is equal to 16. Now just multiply 3 times 4. 16 + 12 = 28.
I am not understanding what this question is asking.
Answer:
|-2y+5|=2|4y-1|
-2y+5=8y-2
-2y-8y=-2-5
-10y=-7
y=7/10
Step-by-step explanation:
Answer:
The sequences which are geometric are
16,-8,4,-2,1
625,125,25,5,1
-15,-18,-21.6,-25.92,-31.104
Step-by-step explanation:
Geometric sequences are ones in which you multiply or divide to get the next terms in the sequence.
Cheers
Step-by-step explanation:
(a²-b²)(c²-d²) = a²c² - a²d² - b²c² + b²d²
(b²-d²)(c²-a²) = b²c² - a²b² - c²d² + a²d²
the sum of both is
a²c² + b²d² - a²b² - c²d² = a²(c²-b²) + d²(b²-c²) =
= a²(c²-b²) - d²(c²-b²) = (c²-b²)(a²-d²) = 2021
after a little check we find 2021 is only divisible by 43 and 47 (or 1 and 2021).
so, it is clear that our expression resembles
43×47 = 2021
that means that e.g. c²-b² = 43, and a²-d² = 47
or the other way around, it does not matter.
what squared integer numbers give a difference of 43 ? and 47 ?
squared numbers
1 4 9 16 25 36 49 64 81 100 121 144 169 196 225 256
289 324 361 400 441 484 529 576
aha ! 484 - 441 = 43
and 576 - 529 = 47
so, we get
a = sqrt(576) = 24
b = sqrt(441) = 21
c = sqrt(484) = 22
d = sqrt(529) = 23
one could also use the formula for consecutive squared numbers
(n+1)² = n² + 2n + 1
under the assumption that the 2 numbers are convective (which it turns out they are in this example) we get
(n+1)² - n² = 2n + 1 = 43
2n = 42
n = 21
n+1 = 22
and for 47
2n + 1 = 47
2n = 46
n = 23
n+1 = 24
