Pls help!!!

Work out (4.2×107)÷(7×104)Give your answer in standard form. Work out (4.2×107)÷(7×104)Give your answer in standard form.

professor190 [17]

Answer:

6 * 10^2

Step-by-step explanation:

Simplify : (4.2×10^7)÷(7×10^4)

(4.2 × 10^7) / (7 × 10^4)

From indices : 10^a ÷ 10^b = 10^(a - b)

(4.2 / 7) * 10^(7-4)

0.6 * 10^3

= 6 * 10^2

Hence, (4.2×10^7)÷(7×10^4) = 6 * 10^2

6 0

3 years ago

You scored a 91 on a test with bonus points. you got 4 bonus points how many points did you score before the bonus points

Alex Ar [27]

You need to subtract the bonus points form the final score: 91-4=87

3 0

3 years ago

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You need to solve a system of equations. You decide to use the elimination method. Which of these is not allowed? 3x-2y=7 equati

svetlana [45]

Answer:

x = 31/9 and y = 5/3

Step-by-step explanation:

It is given that,

3x - 2y = 7 -----(1)

3x + 4y = 17 ----(2)

<u>To find the solution by elimination method</u>

Step 1: Subtract eq(2) from eq(1)

3x - 2y = 7 -----(1)

<u> 3x + 4y = 17 </u>----(2)

0 - 6y = -10

6y = 10

y = 10/6 = 5/3

Step 2: Substitute the value of y in eq (1)

3x - 2y = 7 -----(1)

3x - 2*(5/3) = 7

3x = 7 + 10/3

3x = 31/3

x = 31/9

Therefore x = 31/9 and y = 5/3

5 0

3 years ago

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In triangle abc, the perimeter is 36, and ab=ac. line ad is perpendicular to bc at the point d, and triangle abd's perimeter is

Musya8 [376]

Let x=ab=ac, and y=bc, and z=ad.

Since the perimeter of the triangle abc is 36, you have:

Perimeter of abc = 36
ab + ac + bc = 36
x + x + y = 36
(eq. 1) 2x + y = 36

The triangle is isosceles (it has two sides with equal length: ab and ac). The line perpendicular to the third side (bc) from the opposite vertex (a), divides that third side into two equal halves: the point d is the middle point of bc. This is a property of isosceles triangles, which is easily shown by similarity.

Hence, we have that bd = dc = bc/2 = y/2 (remember we called bc = y).

The perimeter of the triangle abd is 30:

Permiter of abd = 30
ab + bd + ad = 30
x + y/2 + z =30
(eq. 2) 2x + y + 2z = 60

So, we have two equations on x, y and z:

(eq.1) 2x + y = 36
(eq.2) 2x + y + 2z = 60

Substitute 2x + y by 36 from (eq.1) in (eq.2):

(eq.2') 36 + 2z = 60

And solve for z:

36 + 2z = 60 => 2z = 60 - 36 => 2z = 24 => z = 12

The measure of ad is 12.

If you prefer a less algebraic reasoning:

- The perimeter of abd is half the perimeter of abc plus the length of ad (since you have "cut" the triangle abc in two halves to obtain the triangle abd).

- Then, ad is the difference between the perimeter of abd and half the perimeter of abc:

ad = 30 - (36/2) = 30 - 18 = 12

4 0

3 years ago

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Jenny has saved $3,800 over the last 12 months. She saved either $250 or $350 a month. During the 12 month period, how many time

Nana76 [90]

Answer:

Jenny save 4 times $\$ 250$ for the month