54 5 270
------- × ------- = --------- = 45
1 6 6
28 2 56
------- × ------ = ------- = 8
1 7 7
Y = x² + 4x + 4.. Since the coefficient of x² =1, is positive, then this parabola opens upward & has a minimum.
Its axis of symmetry is = -b/a = -4/1 = 4 (so x=4)
1) When x=4, y= 4²+4(4)+4 => y=36 so the VERTEX has a minimum is at (4,36)
2)FOCUS.: To be able to calculate the focus, rewrite the equation in a standard form: y-k =a(x-h)² & y = x² + 4x + 4 could be written y=(x+2)², this means that k=0 & h=-2.
Now p being the distance between the VERTEX & the FOCUS, we apply the formula (x-2)² = 4P (y-k) , but k=0 & h=2 then (x-2)² = 4P(y-0) then P =1/4
3) DRECTRICE : y=k-P = 0-1/4 ==> y=-1/4 is the directrix
x=4
Add Six to both sides and get 3<span>√x-6+6=0+6
Divide both sides by 3 and get x</span><span>√2
</span><span>
Solve the square root and get x=2^2
Square both sides and get x=4
Plug in and get </span><span>3√x -6=0
</span>
Hope it helps
Three million, three hundred eighty eight thousand, one hundred ninety eight
3a x 3=729
9a=729
--- -----
9 9
a=81
The number is 81.
Check: 3(81)x3=729
