The total number of nickels we have is 15.
Given we have 27 coins, made up of nickels, dimes and quarters.
there total value is $3.30
we have 3 times as many quarters as dimes.
total nickels = ?
let, x = number of dimes
3x = number of quarters
y = number of nickels
then, x ₊ 3x ₊ y = 27
therefore, 4x ₊ y = 27 .. eq(1)
total value of coins in cents = 330
10(x) ₊ 25(3x) ₊ 5(y) = 330
10x ₊ 75x ₊ 5y = 330
85x ₊ 5y = 330
17x ₊ y = 66 ..eq(2)
Subtracting (1) from (2):
13x=39
x=3
So the number of dimes is x=3; the number of quarters is 3x=9; and since the total number of coins is 27, the number of nickels is 15.
hence the total number of nickels is 15.
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Answer:
id.k sorry
Step-by-step explanation:
The answer is y = 2x + 0 or y = 2x.
The line passes through (0,0) and (1,2). The slope is
m = (2 − 0)/(1 − 0) = 2.
(You could also see this by drawing the two points and a slope triangle and use the rise/run idea of slope.)
In the slope-intercept form, y = mx + b, you now know that m = 2 and b = 0, so the answer is
y = 2x + 0 or y = 2x.
xy = -20
x + y = 1
x + y = 1
x - x + y = -x + 1
y = -x + 1
xy = -20
x(-x + 1) = -20
x(-x) + x(1) = -20
-x² + x = 20
-x² + x + 20 = 0
-1(x²) - 1(-x) - 1(-20) = 0
-1(x² - x - 20) = 0
-1 -1
x² - x - 20 = 0
x = -(-1) ± √((-1)² - 4(1)(-20))
2(1)
x = 1 ± √(1 + 80)
2
x = 1 ± √(81)
2
x = 1 ± 9
2
x = 0.5 ± 4.5
x = 0.5 + 4.5 or x = 0.5 - 4.5
x = 5 or x = -4
x + y = 1
5 + y = 1
- 5 - 5
y = -4
(x, y) = (5, -4)
or
x + y = 1
-4 + y = 1
+ 4 + 4
y = 5
(x, y) = (-4, 5)
The two numbers that add up to 1 and multiply to -20 are -4 and 5.