-1•f(-9)+7•g(6)= A.32 B.34 C.36 D.38

Mathematics

1 answer:

wlad13 [49]3 years ago

4 0

Answer:

Step-by-step explanation:

-1•f(-9)+7•g(6)

f(-9) is 4

g(6) = 6

-1* 4+7*6

-4 +42

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A = {a, b, c, d}

Rama09 [41]

Answer:

No, Johnny is not correct

A U B = {a,b,c,d,e,f,g,h}

Step-by-step explanation:

Johnny's answer does not have c and d, elements that are in A and B, so A U B must have all elements that belong to A or B.

The (U) represents the sum of elements between two sets. So If a set has three elements {@,#,$} and another set has 5 elements {%,^,&}, (U) equals the sum of these sets: {@,#,$,%,^,&}.

The same is true for the sets A and B.

A = {a, b, c, d}

B = {c, d, e, f, g, h}

A U B = {a,b,c,d,e,f,g,h}

Note: c, d are repeated, in A and B. It is not necessary to write them twice in the final answer.

5 0

3 years ago

Barbara drives between Miami, Florida, and West Palm Beach, Florida. She drives 50 mi in clear weather and then encounters a thu

cluponka [151]

Answer:

<em>Her speed driving in nice weather is 50 mph and in thunderstorm is 32 mph.</em>

Step-by-step explanation:

Barbara drives 50 miles in clear weather and then encounters a thunderstorm for the last 16 miles.

Suppose, her speed in nice weather is $x$ mph.

As she drives 18 mph slower through the thunderstorm than she does in clear weather, so her speed in thunderstorm will be: $(x-18) mph$

<u>We know that,</u> $Time = \frac{Distance}{Speed}$

So, <u>the time of driving in clear weather</u> $=\frac{50}{x}$ hours

and <u>the time of driving in thunderstorm</u> $=\frac{16}{x-18}$ hours.

Given that, <u>the total time for the trip is 1.5 hours</u>. So, the equation will be......

$\frac{50}{x}+ \frac{16}{x-18}=1.5 \\ \\ \frac{50x-900+16x}{x(x-18)}=1.5\\ \\ \frac{66x-900}{x(x-18)}=1.5 \\ \\ 1.5x(x-18)=66x-900\\ \\ 1.5x^2-27x=66x-900\\ \\ 1.5x^2-93x+900=0\\ \\ 1.5(x^2 -62x+600)=0\\ \\ x^2 -62x+600=0\\ \\ (x-50)(x-12)=0$