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3 years ago

-7x - 8y = 9 4x -9y = 22

Mathematics

1 answer:

umka21 [38]3 years ago

8 0

Answer:

x=1 and y=−2

Step-by-step explanation:

Multiply the first equation by 9,and multiply the second equation by -8.

9(−7x−8y=9)

−8(4x−9y=22)

Becomes:

−63x−72y=81

−32x+72y=−176

Add these equations to eliminate y:

−95x=−95

Then solve−95x=−95for x:

−95x

−95

(Divide both sides by -95)

x=1

Now that we've found x let's plug it back in to solve for y.

Write down an original equation:

−7x−8y=9

Substitute1forxin−7x−8y=9:

(−7)(1)−8y=9

−8y−7=9(Simplify both sides of the equation)

−8y−7+7=9+7(Add 7 to both sides)

−8y=16

−8y

−8

(Divide both sides by -8)

y=−2

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Read 2 more answers

Two pedestrians simultaneously left two villages 27 km apart and walked toward each other. the first one walked 4 km per hour, a

Salsk061 [2.6K]

Step 1: Assign variable for the unknown that you need to find.

Let ' t ' be the number of hours it took for the pedestrians to meet.

Step 2: List the give details

Speed of first pedestrian = 4 km/hr.

Speed of second pedestrian = 6 km/hr.

Distance between two pedestrians = 27 km.

Step 3: Set up an equation

The relationship between speed, distance and time is given below:

$Distance= \; Rate \times Time$

The first one walked 4 km per hour, distance traveled by first pedestrian is given below:

$Distance_{1^{st} \; pedestrian} \; = \; 4t\\\\Distance_{2^{nd} \; pedestrian} \; = \; 6t$

Two pedestrians simultaneously left two villages 27 km apart and walked toward each other.

$Distance_{1^{st} \; pedestrian} +Distance_{2^{nd} \; pedestrian} =27\\\\4t+6t=27\\Combine \; Like \; Terms\\\\10t=27\\Dividing \; 10 \; on \; both \; sides\\\\ \frac{10t}{10} = \frac{27}{10} \\Simplifying \; fraction \; on \; both \; sides\\\\t=2.7 \; hours$