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2 years ago

B=3/4a a+b=21 A. a=30 b=15 B.a=371/4 b=-161/4 C. a=20 b=11 D. a=12 b=9

Mathematics

1 answer:

lions [1.4K]2 years ago

6 0

Answer:

D option

Step-by-step explanation:

a + b = 21

Placing value of b as 3/4a,

a + 3/4a = 21

7a/4 = 21

a = 12

Putting value of a in b=3/4a,

b = 3 × 12/4 = 9

a = 12, b = 9

Hope it helps.

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107 = 7 - 2(7b - 1) what does b equal?

topjm [15]

107 = 7 -2 (7b - 1)

First, distribute -2 to all terms within the parenthesis

-2(7b - 1) = -14b + 2

107 = 7 -14b + 2

Combine like terms

107 = -14b (+7 + 2)

107 = -14b + 9

Isolate the b. Note the equal sign, what you do to one side, you do to the other. Do the opposite of PEMDAS.

Subtract 9 from both sides

107 (-9) = -14b + 9 (-9)

107 - 9 = -14b

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Isolate the b. Divide -14 from both sides

(98)/-14 = (-14b)/-14

98/-14 = b

b = −7

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