Question

How do you use cross products to solve `6.8/z=2/5`?

Answer 1

`z=17`

Explanation:

`"given an equation with 2 equal fractions then"`

`•color(white)(x)a/b=c/drArraxxd=bxxc`

`rArrcolor(blue)(6.8)/color(red)(z)=color(red)(2)/color(blue)(5)larr"cross-multiply"`

`rArrcolor(red)(z)xxcolor(red)(2)=color(blue)(6.8)xxcolor(blue)(5)`

`rArr2z=34`

`"divide both sides by 2"`

`(cancel(2) z)/cancel(2)=34/2`

`rArrz=17`

`color(blue)"As a check"`

`"left side "=6.8/17=0.4=2/5=" right side"`

`rArrz=17" is the solution"`