Literally just plug it in
6(7) + 5(-4) - 42 = 0
42 -20 -42 = 0
-20 = 0
Not a solution.
S = n(a1 + an)/2
2S = n(a1 + an)
2S = na1 + nan
nan = 2S - na1
an = (2S - n a1)/n
Answer:
Step-by-step explanation:
(10 pushups)/(25 sec) = (⅖ pushup)/sec
Or,
(25 sec)/(10 pushups) = (2.5 sec)/pushup
First, we need to transform the equation into its standard form (x - h)²=4p(y - k).
Using completing the square method:
y = -14x² - 2x - 2
y = -14(x² + 2x/14) - 2
y = -14(x² + 2x/14 + (2/28)²) -2 + (2/28)²
y = -14(x + 1/14)² - 391/196
-1/14(y + 391/196) = (x + 1/14)²
This is a vertical parabola and its focus <span>(h, k + p) is (-1/14, -391/196 + 1/56) = (-1/14, -775/392).
Or (-0.071,-1.977).</span>
