How do you solve #-\frac { 7} { 4} r = - \frac { 63} { 4}#?

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Answer 1 · 2017-10-27T06:35:13

#r = 9#

#- 7/4r = - 63/4#

You can use as many methods..

#color(blue)("Method 1")#

Comparing the equations!

#- 7/4r = - 63/4#

Since there is equality..

#cancel- 7/cancel4r = cancel- 63/cancel4#

Leaving..

#7r = 63#

Divide both sides by #7#

#(7r)/7 = 63/7#

#cancel(7r)/cancel7 = 63/7#

#r = 63/7#

#r = 9#

#color(blue)("Method 2")#

Cross multiplication!

#- 7/4r = - 63/4#

Cross multiplying..

#4 (-7r) = 4 (-63)#

Divide both sides by #4#

#(4 (-7r))/4 = (4 (-63))/4#

#(cancel4 (-7r))/cancel4 = (cancel4 (-63))/cancel4#

#-7r = -63#

Divide both sides by #-7#

#(-7r)/(-7) = (-63)/(-7)#

#cancel(-7r)/cancel(-7) = (-63)/(-7)#

#r = (-63)/-7#

#r = 9#