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2 years ago

when solving the following system of equations by substitution what would be a correct first step x=y–7 3x+15y=-1

Mathematics

1 answer:

seraphim [82]2 years ago

7 0

Answer:

The first step is to replace the value of x from the first equation with x in the second equation:

x=y-7

3x+15y=-1

3(y-7)+15y=-1

3y-21+15y=-1

18y=-1+21

18y=20

y= $\frac{20}{18}$ = $\frac{10}{9}$

x= $\frac{10}{9}$ $- 7$

x= $- \frac{53}{9}$

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2 years ago

Read 2 more answers

Pythagorean Theorema a=24 b=26 c=?

fredd [130]

Answer: 2√313

Step-by-step explanation:

Pythagorean theorem: a²+b²=c²

c²=a²+b²

c²=24²+26²

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2 years ago

An elevator descends into mine shaft at the rate of 6m/min. If the descend starts from 10m above the ground level , how long wil

AnnyKZ [126]

Answer: Hi!

So first, I'm going to convert "350 below ground level" to -350, as this is what "below ground level" represents.

Now, we should find the total distance traveled. Take the absolute value of -350 (350) and add it to 10, the metres above ground level. This is 360.

We already know the rate of travel; 6m/min. All we have to do now is divide the total distance (360) by the rate of travel (6)!

360 ÷ 6 = 60

So, it took 60 minutes, or one hour, for the elevator to travel down the shaft!

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2 years ago

Jasmin, Quinn, and Maddy are rock climbing. Jasmin is 42 ½ feet below Quinn. Maddy is 67 ¾ feet above Jasmin. What is Maddy's po

ladessa [460]

Answer:

$25\frac{1}{4}$ feet

Step-by-step explanation:

Given

$Maddy = 67\frac{3}{4}$ above Jasmin

$Jasmin = 42\frac{1}{2}$ below Quinn

Required

Determine Maddy's position relative to Quinn's

From the given parameter, one can easily deduce that Quinn is in between Maddy and Jasmin (See attachment)

Using the attachment as a point of reference;

$z = 67\frac{3}{4}$

$x = 42\frac{1}{2}$

The relationship between x, y and z is

$z = y + x$

Make y the subject of formula

$y = z - x$

Substitute the values of z and x

$y = 67\frac{3}{4} - 42\frac{1}{2}$

Convert to improper fractions

$y = \frac{271}{4} - \frac{85}{2}$

Take LCM

$y = \frac{271 - 170}{4}$

$y = \frac{101}{4}$

$y = 25\frac{1}{4}$

Hence; Maddy's position relative to Quinn's is  $25\frac{1}{4}$  feet

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3 years ago

The amount of time it takes an ice cube to melt varies inversely to the air temperature. At 30 degrees Celsius, the ice will mel

Anon25 [30]

Answer:

hope this helps A block of ice melts in 2.5 hours when the temperature is 54 degrees.

Step-by-step explanation:therefore you can increase 2.5 and decrease 54 to whatever number you need

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2 years ago