How do you solve 13A = 65 ?

2 Answers
Dec 12, 2015

color(blue)(A=5

Explanation:

13A=65

A=65/13

color(blue)(A=5

Dec 12, 2015

A=65/13

The explanation gives a very detailed introduction to the method for solving this type of question!

Explanation:

Given: color(brown)(13A=65)

color(brown)("The objective is to get A on its own on one side of the equals sign") color(brown)("and everything else on the other.")
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
color(blue)("There three things that it is very important you remember:")

color(blue)("Point 1:")
If we can change the 13 from 13A into the value of 1 we
would have 1xxA which is the same as just A.

color(blue)("Point 2:")
What you do to one side of the equals you also do the other.
Consider 4=4. This we know to be true. But suppose we subtracted 1 from only the left side we would have 4-1!=4 but if we did this instead; 4-1=4-1 then both sides still have the same value.
color(white)(xxxx)
color(blue)("Point 3")
The same process applies to addition, multiplication, division squaring, taking square roots and so on!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

color(brown)("Changing the 13 into 1")

Multiply both sides by color(blue)(1/13)

color(blue)(1/13xxcolor(brown)( 13A = 65)xx1/13)

giving:

13/13xxA=65/13

1xxA=65/13

But 1xxA is the same as just A giving

A=65/13