(9 - 7 × 3 + 4)²
(9 - 21 + 4)²
(9 - 17)²
(-12)²
144
Answer:

Step-by-step explanation:

To get
you needed to divide the numerator and denominator by 3.
Answer: 1/6
Step-by-step explanation:
Slope is the m in y=mx+b
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
The hydronium ion is H₃O⁺ and its concentration is equivalent to the H⁺ ion concentration. The H⁺ ion concentration is given by:
pH = -log[H⁺]
[H⁺] = 10^(-8.2)
[H⁺] = 6.31 x 10⁻⁹ mole/dm³
The hydronium ion concentration is 6.31 x 10⁻⁹ mole/dm³