Saturday

February 28, 2015

February 28, 2015

Posted by **Ashley** on Thursday, January 29, 2009 at 10:01pm.

2. x=1-4y

2x+7y=3

I need help learning how to do this problem step-by-step

- algebra -
**Reiny**, Thursday, January 29, 2009 at 10:04pmyour 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

- algebra -
**Chopsticks**, Thursday, January 29, 2009 at 10:12pmx = 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

- algebra -
**Chopsticks**, Thursday, January 29, 2009 at 10:14pmOh sorry, I did my math wrong and Divided instead of subtracting.

**Answer this Question**

**Related Questions**

ALGEBRA HELP - When solving the equation, what property was used to go from step...

Algebra 1 - -3x + 6 < 21 I need help in solving this problem step by step. ...

Algebra II - Solving the formula for the indicated variable. I=prt,for r I need ...

algebra 1 - I was just wondering if anybody could explain to me the steps in '...

algebra - would you help me write a logic application for andy has the cards1,5...

Algebra 2 - i need help, step by step, in solving for fractional coefficients. ...

algebra 1 - ELEMENTARY ALGEBRA #3 Page 23 Chapter 3 Lesson 3.02 Solving Multi-...

Algebra - 3x-2=0 Solving for x, need step by step instruction?

math/algebra - solve each of the following systems by substitution. 16) 5x -2y...

Algebra1 - I am solving for linear equations and I'm wondering if I did Step 3 ...