Question

Help me with my math homework

Evaluate the expression for the given value of the variable
1. 9.4X -10.1 when X=7

2. 5c+4d when c=2 and d=5

3. the highest location in a certain foreign country is 15,442 feet above sea level. The lowest point in the same country is 143 feet below sea level. What is the difference between these two elevations?

4. Mark has $225 in his checking account. He writes a check for $116, makes a deposit of $108, and then writes another check for 87$. Find the amount left in his account

5. Simplify the expression
10(X-1)-6(X-1)

5
6. ---- X=40
8

(And if you want you can put the equation, I don't know if it would be too much to ask but it would help me a lot).

Answer 1

1)55.7, 2)30, 3)15,585 feet, 4) $130, 5) 4x-4

Explanation:

1) 9.4x-10.1 when x=7

substitute 7 in for x: 9.4(7) - 10.1

multiply 9.4 and 7 together: 65.8-10.1

subtract: 65.8-10.1=55.7

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2) 5c+4d when c=2 and d=5

substitute 2 in for c and 5 in for d: 5(2) + 4(5)

multiply 5x2 and 4x5 to get: 10+20

add together: 10+20=30

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3) One value is 15422, the other value is -143 because it is below sea level.

Subtract -143 from 15422: 15422 - -143= 15422+143

Add those together: 15422+143=15585

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4)

Subtract 116 from 225 because he is writing a check for 116: 225-116=109

Add 108 to 109 because you are adding money

back into the account: 109 +108=217

Subtract 87 from 217 because he is writing another check: 217-87=130
There is $130 left in his account.

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5) 10(x-1)-6(x-1)

Expand the equation: 10x-10-6x+6

Combine like terms: 10x-6x-10+6

Simplify: 4x-4