Two equations are given below:
a – 3b = 9
a = b – 3
What is the solution to the set of equations in the form (a, b)? (5 points)

(–9, –6)

(–4, –3)

(–6, –3)

(–9, –7)

Question

Two equations are given below:
a – 3b = 9
a = b – 3
What is the solution to the set of equations in the form (a, b)? (5 points)

(–9, –6)

(–4, –3)

(–6, –3)

(–9, –7)

DanielleLove · Answer

you have 2 options, the easy one would be to check by replacing the variables with the numbers

Jebediah · Answer

ok

DanielleLove · Answer

the second one would be to actually work the equation backwards

Jebediah · Answer

ok

dude · Answer

You can substitute b-3 into the first equation
$(b-3) – 3b = 9$
Combine like terms
$-2b-3=9$
Add 3 on both sides
$-2b=12$
Divide both sides by -2
$b=-6$

DanielleLove · Answer

a – 3b = 9
a = b – 3

this equals this b-3-3b=9

dude · Answer

Now we can substitute back into the second equation
$a = -6 – 3\
a=-9$
So:

$(-9,-6)$

Jebediah · Answer

oh okay

Jebediah · Answer

thanks guys

Jebediah · Answer

:P