7th Grade Math · Unit 4
Substitute the given value and decide whether it makes the equation true.
Substitute
Replace the variable with the given value.
Simplify the side that has the variable.
Compare the two sides
If the two sides match, the value is a solution.
If the two sides do not match, the value is not a solution.
A negative value
Put a negative value in parentheses before you multiply.
Then use the sign rules for multiplication.
Every number in the equation is a positive whole number.
2x + 5 = 17
Substitute the given value for the variable.
2 × 6 + 5
17
17 = 17
Both sides match, so this value is a solution.
Answer: Yes
3x + 1 = 13
Substitute the given value for the variable.
3 × 4 + 1
13
13 = 13
Both sides match, so this value is a solution.
Answer: Yes
4x + 2 = 18
Substitute the given value for the variable.
4 × 4 + 2
18
18 = 18
Both sides match, so this value is a solution.
Answer: Yes
5x + 5 = 20
Substitute the given value for the variable.
5 × 3 + 5
20
20 = 20
Both sides match, so this value is a solution.
Answer: Yes
2x + 7 = 19
Substitute the given value for the variable.
2 × 6 + 7
19
19 = 19
Both sides match, so this value is a solution.
Answer: Yes
6x + 3 = 27
Substitute the given value for the variable.
6 × 4 + 3
27
27 = 27
Both sides match, so this value is a solution.
Answer: Yes
2x + 3 = 11
Substitute the given value for the variable.
2 × 5 + 3
13
13 ≠ 11
The two sides are not equal, so this value is not a solution.
Answer: No
3x + 4 = 16
Substitute the given value for the variable.
3 × 5 + 4
19
19 ≠ 16
The two sides are not equal, so this value is not a solution.
Answer: No
4x + 1 = 13
Substitute the given value for the variable.
4 × 2 + 1
9
9 ≠ 13
The two sides are not equal, so this value is not a solution.
Answer: No
5x + 2 = 22
Substitute the given value for the variable.
5 × 3 + 2
17
17 ≠ 22
The two sides are not equal, so this value is not a solution.
Answer: No
3x + 6 = 15
Substitute the given value for the variable.
3 × 4 + 6
18
18 ≠ 15
The two sides are not equal, so this value is not a solution.
Answer: No
The trial value or the coefficient is negative.
−3x + 4 = 10
Substitute the given value for the variable.
−3 × 1 + 4
1
1 ≠ 10
The two sides are not equal, so this value is not a solution.
Answer: No
2x + 8 = 2
Substitute the given value for the variable.
2 × (−3) + 8
2
2 = 2
Both sides match, so this value is a solution.
Answer: Yes
−3x + 10 = 4
Substitute the given value for the variable.
−3 × 2 + 10
4
4 = 4
Both sides match, so this value is a solution.
Answer: Yes
4x + 5 = −3
Substitute the given value for the variable.
4 × (−2) + 5
−3
−3 = −3
Both sides match, so this value is a solution.
Answer: Yes
−2x + 7 = 1
Substitute the given value for the variable.
−2 × 3 + 7
1
1 = 1
Both sides match, so this value is a solution.
Answer: Yes
3x + 12 = 3
Substitute the given value for the variable.
3 × (−3) + 12
3
3 = 3
Both sides match, so this value is a solution.
Answer: Yes
2x + 5 = 1
Substitute the given value for the variable.
2 × (−3) + 5
−1
−1 ≠ 1
The two sides are not equal, so this value is not a solution.
Answer: No
−4x + 9 = 1
Substitute the given value for the variable.
−4 × 3 + 9
−3
−3 ≠ 1
The two sides are not equal, so this value is not a solution.
Answer: No
3x + 4 = 10
Substitute the given value for the variable.
3 × (−2) + 4
−2
−2 ≠ 10
The two sides are not equal, so this value is not a solution.
Answer: No
−5x + 8 = 3
Substitute the given value for the variable.
−5 × 2 + 8
−2
−2 ≠ 3
The two sides are not equal, so this value is not a solution.
Answer: No
4x + 6 = 0
Substitute the given value for the variable.
4 × (−1) + 6
2
2 ≠ 0
The two sides are not equal, so this value is not a solution.
Answer: No
A coefficient or the trial value is a fraction.
13x + 2 = 5
Substitute the given value for the variable.
13 × 9 + 2
5
5 = 5
Both sides match, so this value is a solution.
Answer: Yes
12x + 3 = 7
Substitute the given value for the variable.
12 × 8 + 3
7
7 = 7
Both sides match, so this value is a solution.
Answer: Yes
2x + 1 = 4
Substitute the given value for the variable.
2 × 32 + 1
4
4 = 4
Both sides match, so this value is a solution.
Answer: Yes
23x + 1 = 5
Substitute the given value for the variable.
23 × 6 + 1
5
5 = 5
Both sides match, so this value is a solution.
Answer: Yes
4x + 2 = 5
Substitute the given value for the variable.
4 × 34 + 2
5
5 = 5
Both sides match, so this value is a solution.
Answer: Yes
34x + 1 = 7
Substitute the given value for the variable.
34 × 8 + 1
7
7 = 7
Both sides match, so this value is a solution.
Answer: Yes
12x + 3 = 7
Substitute the given value for the variable.
12 × 6 + 3
6
6 ≠ 7
The two sides are not equal, so this value is not a solution.
Answer: No
2x + 1 = 4
Substitute the given value for the variable.
2 × 12 + 1
2
2 ≠ 4
The two sides are not equal, so this value is not a solution.
Answer: No
32x + 2 = 8
Substitute the given value for the variable.
32 × 2 + 2
5
5 ≠ 8
The two sides are not equal, so this value is not a solution.
Answer: No
3x + 1 = 4
Substitute the given value for the variable.
3 × 23 + 1
3
3 ≠ 4
The two sides are not equal, so this value is not a solution.
Answer: No
14x + 2 = 4
Substitute the given value for the variable.
14 × 4 + 2
3
3 ≠ 4
The two sides are not equal, so this value is not a solution.
Answer: No
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