4y + 2 = 1/2x - 3y solve for y

multiply each equation by the value that makes the coefficients of x opposite

(-2) x (x+3y) = (-2) (1)

2x + 4y = -2

simplify

-2x - 6y = -2

2x + 4y = -2

add the two equations together to remove x from the system

-2x - 6y = -2 + 2x + 4y = -2 = -2y = -4

divide each term by -2 and simplify

y=2

-14

step-by-step explanation:

2x2 – 2(x+4)

=2x2-2（5+4）

=4-2×9

=4-18

=-14

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)