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3 years ago

Evaluate -3 to the 2 power + (2-6)(10)pls hurry i need help on it

Mathematics

1 answer:

stira [4]3 years ago

5 0

Answer:

-31

Step-by-step explanation:

-3 to the power of 2 means -3*-3 and since negative multiplied by negative is positive, that will give 9

9 + (2-6)(10)

9+-4(10)

9+ -40

9-40

-31

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A cone of radius 3cm and slant height 6cm is cut into four identical pieces. Calculate the total surface area of the four pieces

Daniel [21]

Area of cone=3.14*9+3*6*3.14=27*3.14

=84.78 cm^2 if we cut into four identical pieces we get two triangle surfaces also for 1 piece and and 1/4 of the original surface area =21.195+15.588=36.783squarecm

5 0

3 years ago

In triangle △ABC, ∠ABC=90°, BH is an altitude. Find the missing lengths. AC=5 and BH=2, find AH and CH.

Yakvenalex [24]

Answer:

AH = 1 or 4

CH = 4 or 1

Step-by-step explanation:

An altitude divides a right triangle into similar triangles. That means the sides are in proportion, so ...

AH/BH = BH/CH

AH·CH = BH²

The problem statement tells us AH + CH = AC = 5, so we can write

AH·(5 -AH) = BH²

AH·(5 -AH) = 2² = 4

This gives us the quadratic ...

AH² -5AH +4 = 0 . . . . in standard form

(AH -4)(AH -1) = 0 . . . . factored

This equation has solutions AH = 1 or 4, the values of AH that make the factors be zero. Then CH = 5-AH = 4 or 1.

3 0

3 years ago

A motorcyclist leaves City A and rides at a constant speed towards City B, which is 225 km away. After 1.5 hours, the motorcycli

rewona [7]

Answer:

50 km/hr

Step-by-step explanation:

OK, this is how I solved this problem.

Let r = original rate of speed

t = time after the stop to finish the trip

Time for trip without stopping is 225/r

(1) 1.5 + .5 + t = 225/r This is a time equation

(2) 1.5r + t(r + 10) = 225 This is a distance equation

(1) 2 + t = 225/r (2) 1.5r + tr + 10t = 225

2r + tr = 225

tr = 225 - 2r 1.5r + 225 - 2r + 10(225/r - 2) = 225

t = 225/r - 2

-.5r + 225 + 2250/r - 20 = 225

-5r + 2250 + 22500/r - 200 = 2250

-5r^2 + 2250r + 22500 - 200r = 2250r

5r^2 + 200r - 22500 = 0

5(r^ + 40r - 4500) = 0

5(r - 50)(r + 90) = 0

r = 50 or r = -90

The rate cannot be negative, so the original speed 50 km/hr

This not an easy problem and I hope you were able to follow my work

5 0

3 years ago

Read 2 more answers

2 u + 12 < 23 0,1 d + 8 > 0 3 - 4 r > 7 13 < 2 z + 3 6 ≥ 9 - 0, 15 i

BartSMP [9]

Answer:

Part 1) $u< 5.5$

Part 2) $d > -80$

Part 3) $r < -1$

Part 4) $z>5$

Part 5) $i\geq 20$

Step-by-step explanation:

The question is

Solve each inequality for the indicated variable

Part 1) we have

$2u+12$

subtract 12 both sides

$2u< 23-12\\2u$

Divide by 2 both sides

$u< 5.5$

The solution is the interval (-∞,5.5)

In a number line the solution is the shaded area at left of u=5.5 (open circle)

The number 5.5 is not included in the solution

Part 2) we have

$0.1d+8 >0$

subtract 8 both sides

$0.1d > -8$

Divide by 0.1 both sides

$d > -80$

The solution is the interval (-80,∞)

In a number line the solution is the shaded area at right of d=-80 (open circle)

The number -80 is not included in the solution

Part 3) we have

$3-4r> 7$

Subtract 3 both sides

$-4r>7-3\\-4r>4$

Divide by -4 both sides

Remember that, when you multiply or divide both sides of an inequality by a negative number, you must reverse the inequality symbol

$r < -1$

The solution is the interval (-∞,-1)

In a number line the solution is the shaded area at left of r=-1.1 (open circle)

The number -1.1 is not included in the solution

Part 4) we have

$13< 2z+3$

Subtract 3 both sides

$13-3$

Divide by 2 both sides

$5$

Rewrite

$z>5$

The solution is the interval (5,∞)

In a number line the solution is the shaded area at right of z=5 (open circle)

The number 5 is not included in the solution

Part 5) we have

$6\geq 9-0.15i$

Subtract 9 both sides

$6-9\geq -0.15i\\-3\geq -0.15i$

Divide by -0.15 both sides

Remember that, when you multiply or divide both sides of an inequality by a negative number, you must reverse the inequality symbol

$20\leq i$

Rewrite

$i\geq 20$

The solution is the interval [20,∞)

In a number line the solution is the shaded area at right of i=20 (closed circle)

The number 20 is included in the solution

6 0

3 years ago

Jorge finds 56% of his 75 classmates likes salsa music and 80% of his 60 relatives like salsa music.How many more of Jorge’s rel

erica [24]

56% of 75 = 42
80% of 60 = 48

The question asks for the difference, so there are 6 additional people who like salsa music

5 0

3 years ago