[size=150][size=150]What do you mean by values that satisfy an equation ?[br][br][/size]In the equation 3x + 1 = 7, x is unknown.[br][br]But we can solve the unknown x[br]The left side of the equation 3x + 1 equals to the value of 7 on the right of the equation.[br][br]Only one value of x satisfies the equation, ie. if x = 2,[br]the left side of the equation becomes 3(2) + 1 = 6 + 1 = 7 (equals the value on the right)[br][br]We can also solve the equation 3x + 1 = 7 algebraically by this[br]Subtracting 1 from both sides,[br] 3x + 1 - 1 = 7 - 1[br]then 3x = 6[br]Dividing both sides by 3, [br] x = 2[br][br]What about linear equations of two variables?[br]for example 2x + y = 7[br][br]What are the values of x and y which satisfy the equation above?[br][br]If x = 1, and y = 5 [br]the left side of the equation becomes 2(1) + 5 = 7 (equals the value on the right of the equation.[br][br]If x = 2, and y = 3[br]the left side of the equation becomes 2(2) + 3 = 7 (again equals value on the right of equation)[br][br]If x = 1.5 and y = 4[br]the left side of the equation is 2(1.5) + 4 = 7 (again equals value on the right of equation)[br][br]In other words the pairs of values x =1 and y = 5, x = 2 and y = 3, x = 1.5 and y = 4 are possible solutions to the unknowns x and y since they satisfy the equation 2x + y = 7.[br][br]In fact, there are countless number of possible pairs of x and y values that satisfy the equation.[br][/size][br][size=150]With this applet below, find the x and y values that satisfy equations of lines appearing below.[br]How do the pairs of x and y values relate to the equation of the line?[/size]