Solve by using elimination 7) -6x – 8y = -30
4x + 2y = 20

x = 5 , y = 0

Step-by-step explanation by elimination:

Solve the following system:

{-6 x - 8 y = -30 | (equation 1)

4 x + 2 y = 20 | (equation 2)

Add 2/3 × (equation 1) to equation 2:

{-(6 x) - 8 y = -30 | (equation 1)

0 x - (10 y)/3 = 0 | (equation 2)

Divide equation 1 by -2:

{3 x + 4 y = 15 | (equation 1)

0 x - (10 y)/3 = 0 | (equation 2)

Multiply equation 2 by 3/10:

{3 x + 4 y = 15 | (equation 1)

0 x - y = 0 | (equation 2)

Multiply equation 2 by -1:

{3 x + 4 y = 15 | (equation 1)

0 x+y = 0 | (equation 2)

Subtract 4 × (equation 2) from equation 1:

{3 x+0 y = 15 | (equation 1)

0 x+y = 0 | (equation 2)

Divide equation 1 by 3:

{x+0 y = 5 | (equation 1)

0 x+y = 0 | (equation 2)

Collect results:

 {x = 5 , y = 0

x =-.20752

step-by-step explanation:

4^(x+2)=12

4^(x+2)=12

take the log base 4 on each side

log 4 (4^(x+2) = log 4(12)

we know log b(a^y) = y log b (a)

(x+2) log 4(4) = log 4 (12)

x+2 = log 4 (12)

we know   logb c = loga c/loga b

we want to convert to base 10   so a = 10

by default, we do not write the 10   c = 4   and b = 10

log4 10 = log 12/log 4

log4 10 = log 12/ log 4

x+2 = log 12/ log 4

subtract 2 from each side

x +2 -2 = log 12/ log 4 -2

x = 1.79248125 -2

x =-.20752

answer:   c ?

step-by-step explanation: