Answer:
k = - 8
Step-by-step explanation:
Subtract 9 from both sides to get the constants on one side and the variables on the other
9 - 2k = 25
- 2k = 25 - 9
Simplify
- 2k = 16
Divide by -2 on both sides to isolate the variable, then simplify once more.
- 2k/ -2 = 16/ -2
k = 16/ -2
k = -8
1*10^12
Which means like 11 0's at the end of the 10
If the slope of AB = CD and BC = AD it's a parallelogram:
Slope of AB = 6+1 / -9+5 = -7/4
CD = -2-5 / 3+1 = -74
These are equal.
BC = 5-6 / -1 +9 = -1/8
AD = -2 +1 / 3+5 = -1/8
These are also equal so it is a parallelogram.
Now to find if the diagonals are perpendicular find the slope of the perpensicular points:
AC = 5 +1 / -1 +5 = 6/4 = 3/2
BD = 6+2 / -9 -3 = 8/-12 = -2/3
Because BD is the reciprocal of AC, this means they are perpendicular.
And because AB is not perpendicular to AD ( AB and AD are not reciprocals) it is a rhombus.
First thing you should do is reduce coefficients.
1st equation has all multiples of '2'. Divide by 2
---> x +3y = -6
2nd equation has multiples of 5. Divide by 5.
---> x - y = 2
Now elimination part is easier.
Eliminate 'x' variable by subtracting 2nd equation from 1st.
x + 3y = -6
-(x - y = 2)
----------------------
4y = -8
Solve for 'y'
4y = -8
y = (-8)/4 = -2
Substitute value for 'y' back into 2nd equation:
x - (-2) = 2
x + 2 = 2
x = 0
Solution to system is:
x=0, y =-2
Answer:
4 hours
Step-by-step explanation:
120-72=48
48÷12=4
