Which value of x makes the following equation true? 7.8(x - 2) = -0.2x + 40.4

Question

Algebra help. Thanks in advance.

Answer 1

7.8(x–2) = –0.2x+40.4

Multiply each side by 10

(7.8)(10) (x–2) =(10)(–0.2x+40.4)

78(x–2) =(10)(–0.2x+40.4)

Distribute terms using distributive property:  a( b – c) = ab+ac

78x– 156 = – 2x +404

Add 156 and 2x to each side.

80x = 560

Divide each side by 80

x  = 7 is true

Answer 2

7.8(x - 2) = -0.2x + 40.4
7.8x - 7.8 *2 = -0.2 x + 40.4
addition property of equality: if a = b then a + c = b + c
add 0.2x to each side
7.8x - 15.6 + 0.2x = -0.2x + 40.4 +0.2x
8x - 15.6 = 40.4
add 15.6 to each side
8x - 15.6 + 15.6 = 40.4 + 15.6
8x = 56
division property of equality: if a = b then a / c = b / c ( c not equal to zero)
divide each side by 8
x = 7.