Bob wants to sub 3x + y = 13 into 4x +3y = 6 he needs to do what to get this

x = 6.6, y = -6.8

Step-by-step explanation:

Subtract  3 x  from both sides of the equation.

y = 13 - 3x

4x + 3y = 6

Replace all occurrences of  y  with  13  −  3 x  in each equation.

-5x + 39 = 6

y = 13 - 3x

Solve for  x  in the first equation.

x = or 6.6

Replace all occurrences of  x  with 6.6  in each equation.

y = or - 6.8

hope this helps, good luck :)

answer is c

step-by-step explanation:

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)