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3 years ago

Solve the equation 7 + 3m = 28

Mathematics

1 answer:

balandron [24]3 years ago

7 0

The answer is D. M=7

===================
explanation

7+3(7)=28

7+21=28

28=28

making the D.M=7 as true.

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The width of a rectangle is the length minus 2 units. the area of the rectangle is 35 units

Mariana [72]

Answer:

$Length=7units\\\\Width=5units$

Step-by-step explanation:

Width=(Length-2) units

W=(L-2) units

Area of the rectangle= 35 square units

Area = length* Width

$35= L*(L-2)\\\\35=L^2-2L$

Subtracting 35 both sides:

$L^2-2L-35=0$

Solving the quadratic equation for 'L' ;

Using factorization:

$L^2+5L-7L-35=0$

Taking common from the equation :

$L(L+5)-7(L+5)=0\\\\(L+5)(L-7)=0\\\\L+5=0\\\\L=-5$

$L-7=0\\\\L=7$

The length cannot be negative, therefore Length(L)= 7

$Width=Length-2\\\\=7-2\\\\=5 units$

$Length=7units\\\\Width=5units$

8 0

3 years ago

Solve using the elimination method:<br> X-3y=7<br> 3x + 3y=9

sergij07 [2.7K]

Answer:

$x=4\\\\y=-1$

Step-by-step explanation:

Given Equation:

$x-3y=7$ Equation:1

$3x + 3y=9$ Equation:2

Dividing Equation:2 by '3' both the sides:

$x+y=3$

or $x=3-y$ Equation:3

Putting the vale of 'x' in Equation:1

$x-3y=7$

$(3-y)-3y=7\\\\3-y-3y=7\\\\3-4y=7\\\\$

Subtracting '3' both sides

$-4y=7-3\\\\-4y=4$

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

$y=-1$

Putting value of 'y' in Equation:3

$x=3-y$

$x=3-(-1)\\\\x=3+1\\\\x=4$

The solution of the equations is :

$x=4\\\\y=-1$

7 0

3 years ago

If the function f(x)=mx+b has an inverse function, which statement must be true

PIT_PIT [208]

Answer:

The first option .

Step-by-step explanation:

m must not be zero

3 0

3 years ago

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Help asap please I'm stuck and I gotta leave soon

Darya [45]

Answer: I found the answer of A=9h

5 0

3 years ago

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If you wish to warm 40 kg of water by 18 ∘C for your bath, find what the quantity of heat is needed. Express your answer in calo

Harman [31]

Answer:

Quantity of heat needed (Q) = 722.753 × 10³

Step-by-step explanation:

According to question,

Mass of water (m) = 40 kg

Change in temperature ( ΔT) = 18°c

specific heat capacity of water = 4200 j kg^-1 k^-1

The specific heat capacity is the amount of heat required to change the temperature of 1 kg of substance to 1 degree celcius or 1 kelvin .

So, Heat (Q) = m×s×ΔT

Or, Q = 40 kg × 4200 × 18

or, Q = 3024 × 10³ joule

Hence, Quantity of heat needed (Q) = 3024 × 10³ joule

In calories 4.184 joule = 1 calorie

So, 3024 × 10³ joule = 722.753 × 10³

6 0

3 years ago