How do you evaluate #x^2+2x# for the value of x satisfying #5(x-3)+13=4x-3(2-x)#?

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Answer 1 · 2017-08-27T12:09:57

If #x=2#

Then #x^2 +2x = 8#

There are two stages in this question.

Firstly solve the given equation to find a value for #x# which is the solution.

Then substitute that value into the expression to find its value.

#5(x-3)+13=4x-3(2-x)#

#5x-15 +13 = 4x -6+3x" "larr# simplify each side

#5x -2 = 7x -6#

#-2+6 = 7x-5x#

#4 =2x#

#color(blue)(x=2)#

#x^2 +2x" "# becomes:

#color(blue)(2)^2 +2(color(blue)(2))#

#=4+4#

#=8#