Answer:
x=12
Step-by-step explanation:
(9^5)(9^7)=9^x
282429536481=9^x
<em>Step 1: Flip the equation.</em>
9^x=282429536481
<em>Step 2: Solve Exponent.</em>
9^x=282429536481
log(9^x)=log(282429536481)(Take log of both sides)
x*(log(9))=log(282429536481)
x=log(282429536481)/log(9)
x=12
Answer:
Step-by-step explanation:
I have 30 coins, all nickels, dimes, and quarters, worth $4.60. There are two more dimes than quarters. How many of each kind of coin do I have.
..
let quarters be x
dimes = x+2
...
dimes + quarters = x+x+2=2x+2
...
nickels = 30-(2x+2)
...
5(30-(2x+2))+10(x+2)+25x=460
5(30-2x-2)+10x+20+25x=460
150-10x-10+10x+20+25x=460
160+25x=460
-160
25x=460-160
25x=300
/25
x=300/25
x=12 ---- quarters
x+2= 12+2=14 dimes
30-(2x+2)=4 nickels
...
check
4*5+14*10+12*25=20+140+300=460
Answer:
paper clips = $1.85
index cards = $3.95
Step-by-step explanation:
Mark
12 paper clips = x
10 index cards = y
$61.70 total
Janice
15 paper clips = x
7 index cards = y
$55.40 total
12x + 10y = 61.70
15x + 7y = 55.40
*** you want to cancel out one of the letters
(12x + 10y = 61.70) * -7
(15x + 7y = 55.40) * 10
-84x -70y = -431.9
150x + 70y = 554.0
150x + 70y = 554.0
-84x -70y = -431.9
66x + 0 = 122.1
66x = 122.1
x = 122.1 ÷ 66
x = 1.85
plug it back in
15(1.85) + 7y = 55.40
27.75 + 7y = 55.40
7y = 55.40 - 27.75
7y = 27.65
y = 27.65 ÷ 7
y = 3.95
