It'd be easier to do #18 if y ou were to break it up:
14* (first term + 14th term)
Sum from n=1 to 14 of n = S = ---------------------------------
14 2
14(1+14)
= ---------------- = 7(15) = 105
2
The sum of twice that is 210. The sum of "1 from n=1 to n=14" is just 14.
The final sum is 210 + 14 = 224 (answer)
7 1/5th is the anwser but thats easy your just being lazy i think
90 degrees
Hope this helps
Answer:
9.0
Step-by-step explanation:
x = 7 / cos 39°
= 7 / 0.7771
= 9.0
The pair of equations:
y = x + 4
y = -2x - 2
To solve the system of equation by substitution, you would substitute one variable for it's equivalent expression. Combining the pair of equations into one equation in only one variable. The easiest way to do this is by substituting out the variable y because it is already alone on one side of the equal sign. Substitute the y in the second equation for: x+4
x+4 = -2x - 2
solve for x
x + 2x = -2 -4
3x = -6
x = -2
now use the value for x to find y by putting into either equation.
y = x + 4
y = (-2) + 4
y = 2
solution is: (-2, 2)