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3 years ago

What value of r makes this equation true? justify your solution. 0.4r - 7 = -.3r +2.8

Mathematics

2 answers:

Georgia [21]3 years ago

6 0

Answer:

all work is pictured and shown

fiasKO [112]3 years ago

3 0

The answer is 14

0.4r-7=-.3r+2.8

Add 7 to both sides. -7+7=0 so it cancels on the left. 2.8+7=9.8.

0.4r=-.3r+9.8.

Add .3r to both sides. -.3r+3r=0 so it cancels on the right. 0.4r+.3r=0.7r.

0.7r=9.8

Divide 0.7 to both sides. 9.8 divided by 0.7 = 14

So r=14

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Step-by-step explanation:

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As we know the formula for angle between two vectors.

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So, it becomes,

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