Step-by-step explanation:
Remember to isolate the variable for each question. Note the equal sign, what you do to one side, you do to the other.
1) 4 + x = 8
Subtract 4 from both sides
4 (-4) + x = 8 (-4)
x = 8 - 4
x = 4
D) x = 4 is your answer
2) -2x ≤ 6
Note that when dividing or multiplying a negative number, you must flip the sign. Isolate the variable (x).
(-2x)/-2 ≤ (6)/-2
x ≥ 6/-2
x ≥ -3
A & B are the same, so you'll have to ask the teacher which one was supposed to have a negative 3
3) Remember to do the opposite of PEMDAS. First subtract, then multiply. Again, isolate the variable (x).
x/2 + 3 = 5
x/2 + 3 (-3) = 5 (-3)
x/2 = 5 - 3
x/2 = 2
(x/2)(2) = 2(2)
x = 2 * 2
x = 4
A) x = 4 is your answer
4) Remember to do the opposite of PEMDAS. First subtract, then divide. Again, isolate the variable (x).
7x + 6 = 20
7x + 6 (-6) = 20 (-6)
7x = 20 - 6
7x = 14
(7x)/7 = (14)/7
x = 14/7
x = 2
D) x = 2 is your answer
5) You are solving for x. Note that there are two variables, however, you don't need to worry too much about the second variable (<em>a</em>), just know that you cannot combine (using addition or subtraction) a number with variable and a constant (a number without).
First, subtract 8a from both sides:
2x + 8a (-8a) = 10 (-8a)
2x = 10 - 8a
Next, divide 2 from both sides to isolate the variable (x):
(2x)/2 = (10 - 8a)/2
x = (10)/2 (-8a)/2
x = 5 - 4a
D) x = 5 - 4a is your answer
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