For this case we must solve each of the equations proposed:
A) 
We apply distributive property to the terms within parentheses:

Subtracting 6 from both sides of the equation we have:

Dividing between -12 on both sides of the equation:

B) 
We apply distributive property to the terms within parentheses:

We add 5m on both sides of the equation:

Dividing between 2 on both sides of the equation:

C) 
We apply distributive property to the terms within parentheses:

We subtract 14 from both sides of the equation:

Dividing between -7 on both sides of the equation:

D) -
We apply distributive property to the terms within parentheses:

We add 28 to both sides of the equation:

Dividing between -21 on both sides of the equation:

Answer:

Distribute:
3x-12=12
Add 12 over
3x=24
divide by 3
x=8
Answer:
the answer is 10 you round up a nine it keeps going to the end
x should equal -2 and y should equal -3 to solve this i multiplied the first equation by 2 then got rid of the 4y and -4y then i added the 14x to the 9 equaling 23x and added the -40 to the -6 which became 23x=-46 i solved this getting -s for x, then i plugged that into the equations to get y which was -3
Answer:
⇒ The given quadratic equation is x2−kx+9=0, comparing it with ax2+bx+c=0
∴ We get, a=1b=−k,c=9
⇒ It is given that roots are real and distinct.
∴ b2−4ac>0
⇒ (−k)2−4(1)(9)>0
⇒ k2−36>0
⇒ k2>36
⇒ k>6 or k<−6
∴ We can see values of k given in question are correct.