Answer:
x=1 y =15
Step-by-step explanation:
hopefully correct
-5x-2y=13 (i)
3x-y=12
-y=12-3x
y=-12+3x (ii)
substitute ii into i
-5x-2(-12+3x)=13
-5x +24-6x=13
-11x=-11
x=1
substitute x into ii
y=-12+3(1)
y=15
.
. . x=1 and y =15
Its a simultaneous equation:
lets make "x" the used games and "y" the new ones
4x + 2y = 84
6x + y = 78. (multiply this by 2 to cancel out y)
12x + 2y = 156
so now we subtract them:
12x - 4x = 156 - 84
x = 9
used games cost $9
new games cost 78 - 6(9) = $24
Janet has $120 but she already bought 3 NEW games so:
120 - 3(24) = $48 left
48/9 = how many used ones she can buy = 5. something
she can buy 5 used
Answer:
h = 4.5 inches
Step-by-step explanation:
The area of a trapezoid is given by
A = 1/2 (b1+b2) h
We know A b1 and b2
20.25 = 1/2 (5+4)*h
20.25 = 9/2 h
Multiply each side by 2/9 to isolate h
2/9 * 20.25 = 2/9 *9/2 h
4.5 =h
There are 24 hours in one day. when you count from 1-24, (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24) the number 7 shows up twice
Answer:
After 5 hours, the amount of bacteria increased: 7800-6000=1800
After 1 hours, the amount of bacteria increased: 1800/5=360
After 18 hours, the amount of bacteria increased: 360*18 = 6480
=> Total amount of bacteria after 13 hours: 6000+6480 =12480