Answer:
The integers are 4 and 7 or -2 and 1.
Step-by-step explanation:
You can make a system of equations with the description of the two integers.
1. x = y + 3
2. 2x + 2 = y^2
The simplest and the fastest way to solve this system in this case is substitution. You can substitute x for y + 3 in the second equation.
1. x = y + 3
2. 2(y + 3) + 2 = y^2
Now simplify and solve the second one. For convenience, I will just disregard the first equation for now.
2y + 6 + 2 = y^2
y^2 - 2y - 8 = 0
You can factor this equation to solve for y.
(y - 4) (y + 2) = 0
y = 4, y = -2
Now we can substitute the value of y for x in the first equation.
x = 7, x = 1
Answer:
<em>19800 seconds, or 330 minutes, or 5 hours + 30 minutes</em>
Step-by-step explanation:
<u>Number Permutations</u>
We know the phone number has 7 digits, 4 of which are known by Mark. This leaves him 3 digits to guess with. We also know the last one is not zero. The number can be represented as
XXY
Where X can be any digit from 0 to 9 and Y can be any digit from 1 to 9. The first two can be combined in 10x10 ways, and the last one can be of 9 ways, this gives us 10x10x9 = 900 possible permutations.
If each possible number takes him 22 seconds, every possibility will need
22x900=19800 seconds, or 330 minutes, or 5 hours + 30 minutes
6x^2 + 7x - 5 = (3x + 5)(2x - 1)
Its 2x - 1
Answer:
1) x < 1, x > 9
2) 2 < x ≤ 6, -4 ≤ x < 0
Step-by-step explanation:
1) lx - 5l > 4
x - 5 = 4
x = 9
-(x - 5) = 4
x = -4 + 5 = 1
x < 1, x > 9
3) 1 < lx-1l ≤ 5
1 < x-1 ≤ 5
2 < x ≤ 6
1 < -(x-1) ≤ 5
-5 ≤ x-1 < -1
-4 ≤ x < 0
