Posted by Ashley on Thursday, January 29, 2009 at 10:01pm.
your first equation says that
x = 1-4y
so "substitute" 1-4y wherever you see x in the other equation
2x+7y=3
2(1-4y) + 7y = 3
2 - 8y + 7y = 3
-y = 1
y = -1
next sub that y = -1 back into the first equation
x = 1 - 4(-1) = 1+4 = 5
x = 1-4y
2x+7y=3
Starting with the first equation
since x = 1 - 4y
Plug that in to the second equation
2(1-4y)+7y=3
2 -8y + 7y = 3
2 - y = 3
2/2 - y = 3/2
- y = 3/2
Since why can't be negative, move the negative over to the other side
y = -3/2
Okay we found what Y is now plug that into the first equation
x = 1-4(-3/2)
x = 1 + 6
x = 7
so the answer is (7,-3/2)
I'm pretty sure this is right, but I hope a real tutor comes and say for sure
Oh sorry, I did my math wrong and Divided instead of subtracting.
Related Questions
Algebra 2 - 1. What is the first step for solving this system by substitution? ...
Algebra II - What is the first step for solving this system by substitution? DO ...
Algebra 1 - -3x + 6 < 21 I need help in solving this problem step by step...
Math need by 9pm cst - Solve by substitution method. Show step by step process. ...
algebra 1 - I was just wondering if anybody could explain to me the steps in &#...
Algebra II - Solving the formula for the indicated variable. I=prt,for r I need ...
MATH ANALYSIS - I need help solving this problem algebraically, but I need to ...
Algebra - Solving system of linear equations by using the apropiate method name ...
algebra! - how do you solve this by substitution: step by step 1. 5x-y=16 5x+2y=...
math,algebra II - I need someone to explain to me step by step the process of ...
For Further Reading
