Answer:
1. x^4 -x^3 -4x^2 -3
a1 = -7.4
an = an-1 -13.8 (choice 1)
Step-by-step explanation:
f(x) = x^4 -x^2 +9
g(x) = x^3 +3x^2 +12
We are subtracting
f(x) -g(x) =x^4 -x^2 +9 - ( x^3 +3x^2 +12)
Distribute the minus sign
x^4 -x^2 +9 - x^3 -3x^2 -12
I like to line them up vertically
x^4 -x^2 +9
- x^3 -3x^2 -12
-------------------------
x^4 -x^3 -4x^2 -3
2. a1 = -7.4
To find the common difference, take term 2 and subtract term 1
-21.2 - (-7.4)
-21.2 + 7.4
-13.8
an = an-1 -13.8
If you’re looking for the ratio:
75cm = 750mm
250:750
1:3
The answer is 1:3
Answer:
13 l of 15%, 13 l of 25%, 26 l of 70%
Step-by-step explanation:
solutions:
final solution:
This includes 0.45*52l= 23.4 l acid
Let's assume:
- amount of 15% solution= x
- amount of 25% solution= y
- amount of 70% solution= z
- and we have z=2y
so there are 2 equation:
or
- x+y+2y= 52 ⇒ x+3y= 52 ⇒ x= 52- 3y
- 0.15x+1.65y=23.4
- 0.15*(52-3y)+1.65y=23.4
- 7.8-0.45y+1.65y=23.4
- 1.2y=23.4-7.8
- 1.2y= 15.6
--------
- x= 52- 3*13= 13 l
- z= 2y= 2*13= 26 l
Parentheses first: -3+1 = -2
Multiply: -2*2=-4
Subtract: -4-5=-9
Final Answer: -9