Answer:
x = 12
y = 9
12 coins of dimes
9 coins of quartes
Step-by-step explanation:
x ---> coins of dimes
y ---> coins of quartes
x + y = 21
0.1x + 0.25y = 3.45 * 100
x + y = 21 L1
10x + 25y = 345 L2
x = 21 - y
Reemplace in L2
10(21 - y) + 25y = 345
210 - 10y + 25y = 345
15y = 345 - 210
15y = 135
y = 9
x = 21 - y
x = 21 - 9
x = 12
Answer:
i believe the answer is x= 85
Answer:
If you really meant that the number of dogs is 12 greater than 3 times the number of cats then:
3 cats
Step-by-step explanation:
21= number of dogs
c = number of cats
21 = 12 + (3c)
3c = 9
c = 3
Answer:
The answer is 38.
Step-by-step explanation:
n²−5n+2
=(-4)²-5(-4)+2
=16+20+2
=38
Answer:
Step-by-step explanation:
the first method :
s(x) = 2 - x and f(x) = 3x
(s f) (-7) = s(-7) ×f(-7)
but : s(-7) = 2 - (-7) =2+7 = 9
f(-7) = 3(-7) = - 21
so : (s f) (-7) = (9)×(-21) = - 189
the second method :
calculate : (s f) (x) == s(x)×f(x) = (2-x) 3x = 6x - 3x²
(s f) (-7) = 6(-7) -3 (-7)² = - 42 -147 = -189
