5³ is 5x5x5 so that is 125
Except x+12=5x-2
because:
4+12= 5*4-2
16=20-2
16=18 -- which is not true
Answer: x is 20
Step-by-step explanation:
This is ratio
a : c = b : x and d : unknown
a : c = 9 : 12 = 3 : 4 which is 9/12
b : x = 15 : x which is 15 / x
So the proportion will be :
3/4 = 15/x
So Cross multiplying
3x = 90
Divide both side by 3
x = 90/3
x = 20
3(2a+1)=-5(a+6)
First expand the brackets.
6a+3=-5a-30
Now add 5a to both sides.
11a+3=-30
Then subtract 3 from both sides.
11a=-33
Finally divide both sides by 11.
a=- 33/11
=-3
