A = hb/2
A = (15)(11) / 2
A = 165/2
A = 82.5 <===
X=8 i did mental math but 56x-16-x=424
+16 +16
55x=440
/55 /55
x=8
negative multiplied by positives = negative numbers
3 x 5 = -15
negative multiplied by a negative = a positive number
-3 x -2y = +6y
so combine both gets -15 +6y
or a better way to write it is 6y-15
The value of the coin times the number of coins all added up equals the total value of the piggy bank
so
0.05n + 0.10d = 5.60
then they have given us "number of nickels is 8 less than 3 times the dimes"
this translates to
n = 3d - 8
we plug this into our first equation and we get
0.05(3d - 8) + 0.10d = 5.60
now we solve for d
first we can distribute the 0.05
0.15d - 0.40 + 0.10d = 5.60
then we can add the 0.15d and 0.10d together
and get
0.25d - 0.40 = 5.60
then we can add 0.40 to both sides
0.25d = 6.00
then divide both sides by 0.25
d = 6.00 / 0.25 = 24
so we have 24 dimes
then to find nickels, we plug in 24 for d into
n = 3d - 8
and get
n = 3(24) - 8
n = 72 - 8
n = 64
therefore we have
64 nickels
and
24 dimes
