Solve this system of linear equations. separate the x- and y- values with a comma. 8x + 2y =-42 4x + 7y=-3

8x + 2y = -42

4x + 7y = -3

In the first equation, subtract 8x from both sides.

2y = -42 - 8x

Divide all terms by 2.

y = -21 - 4x

Now that we have a value of y, we can plug it into the second equation to solve for x.

4x + 7(-21 - 4x) = -3

Distributive property.

4x - 147 - 28x = -3

Combine like terms.

-24x - 147 = -3

Add 147 to both sides.

-24x = 144

Divide both sides by -24.

x = -6

Now that we have a true value for x, we can plug it into either equation to solve for y.

8(-6) + 2y = -42

-48 + 2y = -42

Add 48 to both sides.

2y = 6

Divide both sides by 2.

y = 3

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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)