7th Grade Math

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200 Equations and Inequalities

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Write the phrase as an algebraic

expression.

1. 3 more runs than the Pirates scored


2. a number increased by eight


3. ten dollars more than Grace has

EXAMPLE 1

Write the phrase as an algebraic

expression.

Words: five dollars more than Jennifer earned

Variable: Let d represent the number of

dollars Jennifer earned.

Expression: d + 5

Identify the solution of each equation

from the list given.

4. 8 + w = 17; 7, 8, 9


5. d - 12 = 5; 16, 17, 18


6. 6 = 3 y; 2, 3, 4


7. 7 ÷ c = 7; 0, 1, 2


8. a + 8 = 23; 13, 14, 15


9. 25 + d = 54; 28, 29, 30


10. 10 = 45 - n; 35, 36, 37

EXAMPLE 2

Is 3, 4, or 5 the solution of the equation

x + 8 = 12?

Value of xx + 8 = (^12) sides equal?Are both
3 3 11 +^8 ≠= 12 12 no
4 4 12 +^8 == 12 12 yes 
5 5 13 +^8 ≠= 12 12 no
The solution is 4 since replacing x with
4 results in a true sentence.
Solve each equation mentally.

11. p + 3 = 9 12. 5 + y = 20


12. 40 = 25 + m 14. 14 - n = 10


13. 47 = x - 3 16. 18 = 25 - h


14. AGE The equation 13 + a = 51 describes
    the sum of the ages of Elizabeth and
    her mother. If a is Elizabeth’s mother’s
    age, how old is Elizabeth’s mother?

EXAMPLE 3n – 6 = 20.nnnnnnnnnnnnn n nnnnnnnnnnnnnnnnnnnn–––^666 6 666666666666666666666666666666666666666666 ============^202020202020202020202020202020202020202020202020202020202020200000000000000000000 ............

Solve 18 = 3 h mentally.

18 = 3 h What number times 3 is 18?

18 = 3 · 6 You know that 3 · 6 is 18.

h = 6

The solution is 6.

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