Question #b7543

3 Answers
Jan 10, 2018

Answer:

To solve for x, divide by 0.8.

#x=15.625#

Explanation:

This is a linear equation.

To solve we divide by the coefficient (0.8) in this case.

#therefore x = 12.5/0.8 = 15.625 #

If you didn't have a calculator, leaving it as a fraction is fine :) .

Jan 10, 2018

Answer:

#x=15.625#

Explanation:

Divide each side by 0.8
Since we are trying to find out what #x# equals and not what #0.8x# equals, we need to get rid of the 0.8. Dividing a number by itself always results in 1.

Jan 14, 2018

Answer:

#15.625#

A none calculator 'cheat type' approach
Takes longer to explain than do the actual calculations. Also demonstrates 'distributive' property of multiplication in step 3.

Explanation:

If it is the decimals that are giving you a problem this is a way round it (for this question).

Given: #12.5=0.8x#

Multiply both sides by 10

#125=8x#

Divide both sides by 8. This changes #8x" into "8/8x->1xx x = x#

#x=125/8#
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Bit of a cheat type approach (not really)

Note that #2xx2xx2=8# so #1/2xx1/2xx1/2=1/8#

So if we apply three lots of #xx1/2# we end up with #125-:8#
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(brown)("Step 1"->1/2xx125=62.5)#

#color(brown)("Step 2 "->1/2xx62.5= 31.25)#

Next step has to be 'jiggled' about a bit as part of it is #1=-:2#
Note that #31.25" is the same as "30.25+1#

#color(brown)("Step 3")#

#->1/2(color(white)("d")30.25color(white)("ddd.")+color(white)("ddd")1)#

#color(brown)(->(1/2xx30.25) +(1/2xx1) =(15.125)+(0.5) = 15.625)#