2. Solving Systems Using Substitution
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Make a table of values to organize the given information. Then, using the table create a system of equations.
2.75 seconds
We can use the given information to create a system of equations.
| Firework A | Firework B | ||
|---|---|---|---|
| Verbal Expression | Algebraic Expression | Verbal Expression | Algebraic Expression |
| Number of seconds (s) | x- 0.25 | Number of seconds (s) | x |
| Speed (ft/s) | 220 | Speed (ft/s) | 200 |
| Height (ft) | 220( x- 0.25) | Height (ft) | 200 x |
| Set the equation | y= 220( x- 0.25) | Set the equation | y= 200 x |
Using this table, we can create the system as follows. y=220(x-0.25) & (I) y=200x & (II) The fireworks are set to explode at the same height, so to determine the time at which the firework explodes we must solve for x. To do this, we will use the Substitution Method and substitute the second equation into the first one.
(I):y= 200x
(I):Distribute 220
(I):LHS-220x=RHS-220x
(I):.LHS /(- 20).=.RHS /(- 20).
After 2.75 seconds the fireworks will explode at the same height.