SAT problem: For what values of a and b are the following equations both true?
a+2b+1
-3a-8b=1

I got to where i have gotten only one variable and i
am looking for a. Please explain in detail!

Question

SAT problem: For what values of a and b are the following equations both true?
a+2b+1
-3a-8b=1

I got to where i have gotten only one variable and i 
am looking for a. Please explain in detail!

anonymous · Answer

*a+2b=1

anonymous · Answer

a=3/7, b=-4/7

anonymous · Answer

sorry wrong

anonymous · Answer

the book says after eliminating one of the variables you get -3a-1=4-4a but i have no clue where THAT equation came from

anonymous · Answer

2b=1-a.
so 8b=4(1-a)

anonymous · Answer

sub 8b in eq2

myininaya · Answer

multiply the first equation by 3 to receive 3a+6b=3
now add to the other equation:            +(-3a-8b=1)
                                                       --------------
                                                             0a-2b=4
                                                                 -2b=4
                                                                    b=-2

anonymous · Answer

to eliminate one of them, try multiplying the first equation by 4

4a + 8b = 4
-3a -8b = 1

now add both equations together

a = 5
b = -2

myininaya · Answer

now plug b=-2 into one of equations given to you and solve for a

anonymous · Answer

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