Question

Or which equation would x = 4 be a solution?

Answer 1

$2x+7=22\ \ \ \ |-7\\2x=15\ \ \ \ \ |:2\\x=7.4\neq4\\----------------------\\6x\div8=3\ \ \ \ |\cdot8\\6x=24\ \ \ \ |:6\\x=4\\-------------------\\8-3x=20\ \ \ \ |-8\\-3x=12\ \ \ \ |:(-3)\\x=-4\neq4\\---------------------\\2x+8=4\ \ \ \ \ |-8\\2x=-4\ \ \ \ \ |:2\\x=-2\neq4\\\\Answer:\ 6x\div8=3$

Other method.

Enter the value of x for each equation and check the equality of the pages of the equation

$2x+7=22\\L=2(4)+7=8+7=15;\qquad R=22\qquad L\neq R\\\\6x\div8=3\\L=6(4)\div8=24\div8=3;\qquad R=3;\qquad L=R\\\\8-3x=20\\L=8-3(4)=8-12=-4;\qquad R=20;\qquad L\neq R\\\\2x+8=4\\L=2(4)+8=8+8=16;\qquad R=4;\qquad L\neq R$