7th Grade Math

106 Integers

SUBMERSIBLES A submersible is diving from the surface of the

water at a rate of 90 feet per minute. What is the depth of the

submersible after 7 minutes?

If the submersible descends 90 feet per minute, then after

7 minutes, the vessel will be at 7(-90) or -630 feet. The

submersible will descend to 630 feet below the surface.

f. FINANCIAL LITERACY Mr. Simon’s bank automatically deducts a

$4 monthly maintenance fee from his savings account. What

integer represents the change in his savings account from one

year of fees?

Negative numbers are often used when evaluating algebraic

expressions.

Evaluate Expressions

ALGEBRA Evaluate pqr if p = - 3, q = 4, and r = - 1.

pqr = - 3 (4)(-1) Replace p with -3, q with 4, and r with -1.

= (-12)(-1) Multiply -3 and 4.

= 12 Multiply -12 and -1.

g. Evaluate xyz if x = - 7, y = - 4, and z = 2.

Real-World Link

The MIR submersible

that explored the

Titanic shipwreck was

able to descend to

• 20,000 feet.

RRR

T

Examples 1 and 2 Multiply.

1. 6(-10) 2. 11(-4) 3. - 2(14) 4. - 8(5)

Examples 3–5 Multiply.

5. 
   
   
   
   • 15(-3) 6. - 7(-9) 7. (-8)^2
   
   
   
   


6. (-3)^3 9. - 1(-3)(-4) 10. 2(4)(5)

Example 6 11. MONEY Tamera owns 100 shares of a certain stock. Suppose the price of

the stock drops by $3 per share. Write a multiplication expression to find

the change in Tamera’s investment. Explain your answer.

Example 7 ALGEBRA Evaluate each expression if f = -1, g = 7, and h = -10.

12. 5 f 1313 fgh

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