Let’s solve each expression one by one. I’ll go step by step and check my work carefully.
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1. Evaluate 3x - 2 for x = -7
Plug in x = -7:
3*(-7) - 2 = -21 - 2 =
-23
✔ Check: 3 times -7 is -21, minus 2 is -23 → correct.
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2. Evaluate -x² + 2 for x = 5
Important: This is -(x²), not (-x)². So first square x, then apply the negative.
x = 5 → x² = 25 → -25 + 2 =
-23
✔ Check: 5 squared is 25, negative of that is -25, plus 2 is -23 → correct.
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3. Evaluate xy + 1 for x = 6 and y = -4
Multiply x and y first: 6 * (-4) = -24
Then add 1: -24 + 1 =
-23
✔ Check: 6 times -4 is -24, plus 1 is -23 → correct.
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4. Evaluate -4x + 9 for x = 8
-4 * 8 = -32
-32 + 9 =
-23
✔ Check: -32 + 9 is indeed -23 → correct.
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5. Evaluate x³ + 1 for x = 2
2³ = 8
8 + 1 =
9
✔ Check: 2*2*2=8, +1=9 → correct.
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6. Evaluate 3x² + 2x - 7 for x = 2
First, x² = 4 → 3*4 = 12
2x = 2*2 = 4
So: 12 + 4 - 7 = 16 - 7 =
9
✔ Check: 12+4=16, 16-7=9 → correct.
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7. Evaluate 3(x - 1) - 3 for x = 5
Inside parentheses: 5 - 1 = 4
Multiply by 3: 3*4 = 12
Subtract 3: 12 - 3 =
9
✔ Check: 3*(4)=12, 12-3=9 → correct.
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8. Evaluate |x| - 1 for x = -10
Absolute value of -10 is 10
10 - 1 =
9
✔ Check: |-10|=10, 10-1=9 → correct.
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9. Evaluate 7x - 21 for x = 3
7*3 = 21
21 - 21 =
0
✔ Check: 21 - 21 = 0 → correct.
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10. Evaluate -x² + 25 for x = 5
Again, this is -(x²), so x² = 25 → -25 + 25 =
0
✔ Check: -25 + 25 = 0 → correct.
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11. Evaluate |x| - 8 for x = -8
|-8| = 8
8 - 8 =
0
✔ Check: absolute value makes it positive 8, minus 8 is 0 → correct.
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12. Evaluate x²y³ - 8 for x = 1 and y = 2
x² = 1² = 1
y³ = 2³ = 8
So: 1 * 8 = 8
8 - 8 =
0
✔ Check: 1*8=8, 8-8=0 → correct.
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All answers checked and verified.
Final Answer:
-23, -23, -23, -23, 9, 9, 9, 9, 0, 0, 0, 0
Parent Tip: Review the logic above to help your child master the concept of evaluate expressions worksheet.
