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3 years ago

If 3a + 2b = 7 and 2a + 2b = 9 , what is the value of

1 answer:

3 0

Hey there :)

We have two equations:
3a + 2b = 7
2a + 2b = 9

We need to solve simultaneously to find the values of a and b

eq.1 3a + 2b = 7
eq.2 ( 2a + 2b = 9 ) x -1 ) multiply by -1 to cancel 2b

3a + 2b = 7
- 2a - 2b = -9 ( Add both together )
-------------------
a = - 2

Substitute the value you found for a in a in order to find b

3( - 2 ) + 2b = 7 2( - 2 ) + 2b = 9
- 6 + 2b = 7 OR - 4 + 2b = 9
2b = 13 2b = 13
b = $\frac{13}{2}$ b = $\frac{13}{2}$

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6 0

3 years ago

Read 2 more answers

Truck A costs $600 more that Truck B. However, it burns 0.06 gallon/mile compared to 0.07 gallon/mile for truck B. Both trucks h

qwelly [4]

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Let C and S represent the cost and salvage value of Truck B, respectively. Let X represent the number of miles per year that answers the question.

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3 years ago

What is the value of x in the following equation? 5x + 12 = 6(x + 1) <br> A. 6 <br> B. 5 C. 24 D. 7

Maurinko [17]

Answer:

A: 6

Step-by-step explanation:

Our equation is 5x+12=6(x+1)

Our possible numbers are 6, 5, 24, or 7.

To figure this out you start putting the possible numbers in place of x so we'll start off using 6:

5*6+12=6(6+1).

5*6=30. 30+12=42. 6+1=7, 6*7=42.

This equals the same on both sides.

Next we'll go to 5:

5*5+12=6(5+1)

5*5=25, 25+12=37. 5+1=6, 6*6=36.

This doesn't equal the same amount on both sides.

Next is 24:

5*24+12=6(24+1)

5*24=120, 120+12=132. 24+1=25, 6*25=150

This doesn't equal the same amount.

Next is 7:

5*7+12=6(7+1)

5*7=35, 35+12=47. 7+1=8, 6*8=48.

This doesn't equal.

The only number that equals the same amount on both sides is A:6

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3 years ago