Is it a Bird..is it a Plane....
No it's Substitution!!!!
| So how do I solve a linear equation with substitution you may ask....well watch and learn! | 3x + 4y =
-4.................First Equation x + 2y = 2.....................Second Equation |
| First, Solve equation 2 for x. x + 2y = 2 x + -2y + 2 |
Write Equation 2 Revised equation 2 |
| Next, substitue the expression
for x into Equation 1 and solve for y. 3x + 4y = -4 3(-2y+2) + 4y = -4 y = 5 |
Write Equation 1. Substitue -2y + 2 for x Solve for y |
| Lastly, Substitute the value of y
into the revised Equation 2 and solve for x. x = -2y + 2 x = -2(5) + 2 x = -8 |
|
| The Solution is (-8,5) | |
Time for a word problem!!!!
Your portable stereo requires 10 size D batteries. You have $25 to spend on 5 packages of 2 batteries each and would like to maximize your battery power. Each regual package of batteries costs $4.25 and each alkaline package of batteries costs $5.50 (beacuase alkaline batteries last longer). How many packages of eah type of battery should you buy?
Find the equations first |
4.25x
+ 5.50y = 25 |
Solve for one of the varibles |
x
+ y = 5 |
Plug the solve varible into the otehr equation and solve |
4.25x
+ 5.50( -x + 5 ) = 25 |
Plug the solved x into an equation to solve for y |
x
+ (2) = 5 |