Answer:
8 problems per day for 12 of the days and 9 problems per day for 24 of the days
Step-by-step explanation:
whatever 312 divided by 36 is
Answer:
x = 2
y = -3
Step-by-step explanation:
Solve by substitution:
2x - y = 7
Move the 2x to the other side: -y = 7 - 2x
Divide by -1: y = -7 + 2x
Take the other equation: 3x + y = 3
Substitute y in: 3x + (-7 + 2x) = 3
Take out the parenthesis: 3x - 7 + 2x = 3
Move -7 to the other side: 3x + 2x = 3 + 7
Simplify: 5x = 10
x = 2
Take the first equation: 2x - y = 7
Substitute x back in: 2(2) - y = 7
Simplify: 4 - y = 7
-y = 3
y = -3
12 /2=6 then 6 squared =36
Add 36 to both sides
As we can find that
-8² is -8 x -8 and -7² is -7 x -7
It has the same meaning with rules of positive and negative numbers operation in math :
- If a negative value timed/divided by a negative value, the result is a positive value.
- if a positive value timed/divided by a negative value or vice versa, the result is a negative value.
13.15 ounces of 72% acid and 71.85 ounces of 25% acid are needed
<u>Step-by-step explanation:</u>
Total mass of acid required= 85 ounces
Let the mass of 72% acid be 'a'
Let the mass of 25% acid be 'b'
a + b = 85
b = 85-a
85(40/100) = a(72/100) + b(25/100)
85(2/5) = a(72/100) +(85- a) (25/100)
34 = (72a/100) + (2125/100) - (25a/100)
34 - (2125/100) = (72a + 25a) /100
(3400-2125)/100 = 97a /100
97a = 1275
a = 13.15 ounces
b = 85 - 13.14
b = 71.85 ounces
13.15 ounces of 72% acid and 71.85 ounces of 25% acid are needed
