Question

HELP, i need help!!!!!!!!!!!!!!

Answer 1

Let's find

• h=126t-16t²

Put h=50

• -16t²+126t=50
• -16t²+126t-50=0

Use quadratic formula

`\\ \rm\Rrightarrow t=(-126\pm√(126²-4(-16)(-50)))/(-32)`

`\\ \rm\Rrightarrow t=7.5s,0.4s`

Answer 2

t = 7.46, 0.42

Step-by-step explanation:

h = 126t - 16t² [ "h" is height, "t" is time ]

when height is 50 feet

• 126t - 16t² = 50

• -16t² +126t -50 = 0

• 16t² -126t +50 = 0

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`\sf use \ quadratic \ formula : x = ( -b \pm √(b^2 - 4ac))/(2a) \ \ when \ ax^2 + bx + c = 0`

==================

`\Longrightarrow \sf t = (-126\pm √(126^2-4\left(-16\right)\left(-50\right)))/(2\left(-16\right))`

`\Longrightarrow \sf t = (63\pm√(3169))/(16)`

`\Longrightarrow \sf t = 7.46, \ 0.42`