Question

Given the following two equations, what is the value of a? a + 2b =12 2a + b = 6 3 4 -3 6 0

Answer 1

solve a for one of the equations and substitute that a into the other equation. Now you can find the value of b, and using that value for b in the first equation will give you the value of a.

a + 2b = 12
a = 12 - 2b

Substituting into second equation with a = 12 - 2b

2a + b = 6 thusly becomes -> 2(12-2b) = 6
24 - 4b = 6
-4b = 6 - 24
b = -18/-4 => b = 4.5

Now use this b in the first equation a + 2b = 12
a + 2*4.5 = 12
a = 12 - 9 => a = 3.

You can use the b you found in anywhere you would like to find a. Hope this helped.

Answer 2

a + 2b =12
2a + b = 6

give you 2 ways to solve
first:
get rid of b we do that by mult. 2nd equation by -2
so
a + 2b =12
-2(2a + b = 6 )
we get
a + 2b =12
-4a +-2b = -12
add the 2 equations
3a+0=0
so a = 0 and b would = 6 plugging them back makes the equation true

second way:
a + 2b =12
solve for a, subtract 2b both sides
a=12-2b
take this and sustitute in 2nd equation for a
2(12-2b)+ b = 6
24-4b+b=6
24-3b=6
subtract 24 both sides
-3b=-18
b=6

plug this back in original equations

Answer 3

Wow.. thanks guys