Solve the following equations for a

[lmae]

Hi folks,

Need some help on the following equations. I have never been great with maths, algebra especially, and am struggling to understand.Solve the following equation for a:
Q1: 15/a=-10

Q2: Solve for a in the equation: a+5/4+a-6/3=1/6

Any help is greatly appreciated.

 

[Greg]

Hi lmae and welcome to MHB! :D

Q1:

15/a = -10

Multiply through by a:

15 = -10a

Rearrange and simplify:

a = -15/10 = -3/2

Make sense?

Q2: Solve for a in the equation: (a + 5)/4 + (a - 6)/3 = 1/6

Multiply through by the least common multiple of 4 and 3, which is 12:

3(a + 5) + 4(a - 6) = 2

O.k? Can you continue?

 

[lmae]

Hi,

Thanks very much for the help. The first now makes total sense to me and was able to complete a whole bunch correctly, so a big thanks!

The second one I am still struggling with. Is that the final answer there? Or should I be doing more working out to get to another answer?

 

[Greg]

3(a + 5) + 4(a - 6) = 2

Distribute:

3 * a + 3 * 5 + 4 * a - 4 * 6 = 2

3a + 15 + 4a - 24 = 2

Combine like terms:

3a + 4a + 15 - 24 = 2

7a - 9 = 2

7a = 2 + 9

7a = 11

a = 11/7