Question

4 (x+5)+3 (x+5)=21

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Answer 1

4 (x+5)+3 (x+5)=21
4x + 20 + 3x + 15 = 21
7x + 35 = 21
7x = 21 - 35
7x = -14
x = -14/7
x = -2

Answer 2

4(x+5)+3(x+5)=21 => 4x+20+3x+15=21 => 7x+35=21 => 7x+35-21=0 => 7x+14=0 => 7x=-14 => x=-14/7 => x= -2