Times 2nd equation by 2
add to first equation

3x+6y=6
4x-6y=8 +
7x+0y=14

7x=14
divide both sides by 7
x=2

sub back

2x-3y=4
2(2)-3y=4
4-3y=4
minus 4 both sideds
-3y=0
y=0

(x,y)
(2,0)

8 0

3 years ago

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The height in feet, h, of a model rocket t seconds after launch is given by the equation h(t) = 3+70t - 16t^2. The average rate

andriy [413]

Answer:

The average rate of change

$\frac{dh}{d t} = 70 (1) - 16(2t)$

At t = 1

$\frac{dh}{d t} = 70 (1) - 16(2t) = 38$

at t=3

Step-by-step explanation:

Step(I):-

The given function h(t) = 3+70t - 16t²

$\frac{dh}{d t} = 70 (1) - 16(2t)$

The $\frac{dh}{d t} = 70 (1) - 16(2t) =0$

70 - 32 t = 0

⇒ 70 = 32 t

⇒ $t = \frac{70}{32} = \frac{35}{16}$

Step(ii):-

The average rate of change in h(t) between t = 1 second and t = 3 second

$\frac{dh}{d t} = 70 (1) - 16(2t)$

At t = 1

$\frac{dh}{d t} = 70 (1) - 16(2t) = 38$

At t = 3

8 0

2 years ago