Wednesday
October 22, 2014

Homework Help: Substitution Method in Algebra!HELP PLZ!

Posted by Matthew on Sunday, November 5, 2006 at 5:54pm.

Use the Substitution method to solve the system of equations.

3x + y = 5
4x - 7y = -10

multiply first equation by 4
multiply second equation by 3
thus both equations have same x or y value in this case it is the x value.

12x + 4y = 20
12x - 21y = -30

solve by elimination then plugin values back of x into equation to find y.

So what would the next step be?Can you solve at least half of it for me?

okay well subustitiion is pretty easy!
you have to solve for x and y right?
well take the equation that has x or y by itslef in this case:
3x + y = 5
and solve for y!
y=5-3x
well you may ask why I did that well put y=5-3x into the second equation and solve for x!
okay if id no't get it!
4x - 7y = -10
4x - 7(5-3x) = -10

now do the rest solve for x!

after you have x you put into the first equation you used whcih was
3x + y = 5
and solve for y
show me thew work you did and what your answer is and I will check it for you!


Does x= 1.343
Also,y=2?
PLease help me!!!LOL!Can you help m with all the problems I need help with?

3x+ y = 5
y = 5 - 3x

therefore
4x - 7(5-3x) = -10
4x - 35 + 21x = - 10
25x = 25
x = 1

therefore

plug x back into either equation

so 3*-1 + y = 5
y = 5 -3
y = 2

Oh OK!Thanks can you help me with the rest of my problems that I don't get??PLz!!!

MY BAD SORRY!!!!!

maybe, maybe not...

PLz!But I am going to start a new topic thing at the top because it is getting hard to come all the way done here to respond!PLZ HELP!

x= -1 + 2y
x= 9 - 2y

Solve each system by the substitution method if there is no solution or an infinity number of solution, so state and use notation to express solution set.
n=53p+1600 53+1600 =
n=75+320 75+320= n=395


Determine whether the given ordered pair is a solution of the system.
x+2y=5
2x-y=15


Pg 261
How many calculations can be sold and supplied at $12 per calculator.
a)Per calculator.
B)Find the price at which supply and demand are equal. At this price, how many calculators of this type can be supplied and sold each week.


3x-y=11
2x-5y=13



2(2x-3y)=0
7x=3(2y+3)+2

Pg 282 #4
The sum of three times a first number and twice a second number is 43. If the second numbers subtract from twice the first number, the result is-4. Find the numbers.
Pg 284 #20
Avocado Calories 650 Carbohydrates 86
Apple Calories 10 Carbohydrates

y=2.5

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