Answers:
IF: x = -2, THEN: y = 8
IF: x = 1, THEN: y = 2
IF: x = 3, THEN: y = -2
Isolate the variable, y. Note the equal sign, what you do to one side, you do to the other. When isolating, do the opposite of PEMDAS. When solving, follow PEMDAS.
If: x = -2
Plug in -2 for x in the equation.
2y + 4 (-2) = 8
First, multiply. Note that when you multiply a negative and a positive number, your answer will be negative:
2y + (4 * -2) = 8
2y - 8 = 8
2y - 8 = 8
Isolate the variable, y. First, add 8 to both sides:
2y - 8 (+8) = 8 (+8)
2y = 8 + 8
2y = 16
Next, divide 2 from both sides of the equation:
(2y)/2 = (16)/2
y = 16/2
y = 8
IF x = -2, then y = 8.
If: x = 1
Plug in 1 for x in the equation.
2y + 4(1) = 8
First, multiply:
2y + (4 * 1) = 8
2y + 4 = 8
Next, isolate the variable, y. Note the equal sign; do the opposite of PEMDAS.
First, subtract 4 from both sides:
2y + 4 (-4) = 8 (-4)
2y = 8 - 4
2y = 4
Next, divide 2 from both sides to isolate y:
(2y)/2 = (4)/2
y = 4/2
y = 2
If: x = 1, then y = 2.
If: x = 3
Plug in 3 for x in the equation:
2y + 4(3) = 8
First, multiply:
2y + (4 * 3) = 8
2y + 12 = 8
Next, isolate the variable, y. Note the equal sign; do the opposite of PEMDAS.
First, subtract 12 from both sides of the equation:
2y + 12 (-12) = 8 (-12)
2y = 8 - 12
2y = -4
Next, divide 2 from both sides of the equation:
(2y)/2 = (-4)/2
y = -4/2
y = -2
If: x = 3, then y = -2.
