How do you evaluate #\frac { 2} { 5} ( x - 4y ) + \frac { 1} { 2} ( 2x + y )# if # x = 1; y = - 6#?

1 Answer
smendyka
Aug 7, 2017

See a solution process below:

Explanation:

Substitute #color(red)(1)# for each #color(red)(x)# in the expression. And, substitute #color(blue)(-6)# for each #color(blue)(y)# in the expression. Then calculate the result:

#2/5(color(red)(x) - 4color(blue)(y)) + 1/2(2color(red)(x) + color(blue)(y))# becomes:

#2/5(color(red)(1) - (4 * color(blue)(-6))) + 1/2((2 * color(red)(1)) + color(blue)((-6))) =>#

#2/5(color(red)(1) - (4 * color(blue)(-6))) + 1/2((2 * color(red)(1)) - color(blue)(6)) =>#

#2/5(color(red)(1) - (-24)) + 1/2(2 - color(blue)(6)) =>#

#2/5(color(red)(1) + 24) + 1/2(2 - color(blue)(6)) =>#

#(2/5 xx 25) + (1/2 xx -4) =>#

#(2/color(red)(cancel(color(black)(5))) xx color(red)(cancel(color(black)(25)))5) + (1/color(blue)(cancel(color(black)(2))) xx -2color(blue)(cancel(color(black)(4)))) =>#

#10 - 2 =>#

#8#

Related questions
Impact of this question
1003 views around the world
You can reuse this answer
Creative Commons License