X cannot equal +2, and can't be -1. If you factor it, then you notice you get 2(x+2)(x-2). If you use either one for the x, one will be zero and the won't, and vise-versa.
Answer:
The answer is 42 have a great day.
Step-by-step explanation:
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Let h(t) represent the height of the projectile after t seconds. If the projectile is being launched from the ground, then h(0)=0, and h(t)=-4.9t²+98t. When the equation is in this form, the maximum height is determined by -98/2(-4.9), or after 10 seconds. Thus
-4.9(100)+98(10)=490 m as the highest point of the projectile
Then, when it hits the ground, h(t)=0, so
0=-4.9t²+98t
98t=4.9t²
4.9t=98
t=20
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