Solve the Systems of Equation using Substitution y=x-4

4x - 6y=-16​

x=20 and y=16

Step-by-step explanation:

4x - 6y= -16

since y=x -4, we substitute it in place of "y"

Then, 4x - 6(x-4) = -16

4x - 6x + 24 = -16

-2x+24= -16

-2x= -16-24

-2x= -40

Divide both sides by -2 then,

x=20

once we get the value of "x" we substitute in place of "y=x-4"

y=20-4

y=16

they are simplified

step-by-step explanation:

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15