Algebra Help! (1 Viewer)

[Beege]

I kinda suck at this topic and can someone help me on how to do this question.

1. c^2 = a^2 + b^2 - 2abx

Make x the subject of the formula

2. D = yA
___
y + 12

where y is the age in years and A is the adult dosage. How old is Alex if his medicine dosage is 2.4mL when the adult dosage is 12mL.

3. 1.8^x = 30
What is x?

 

[jb_nc]

1) Um the subject means x = ... Pretty easy, just cary swap c² and 2abx then givide by 2ab.

2) Sub in A = 12, D = 2.4, times everything by the denomiator, expand the left hand side to 2.4y + 28.8 = 12y, then solve for y.

3) 1.8^x = 30
= ln 1.8^x = ln 30
x = ln 30/ ln1.8
x ~ 5.7864487