Explanation for Question 10 From the Math (No Calc) Section on the 2018 April Sat
Question 10 says in the equation above C is a constant. 2 If the equation has infinitely many solutions, 3 what is the value of C? So for an equation to have infinitely 4 many solutions, the left side and the right side have to be the same. 5 So I'm just going to start by factoring out two XC. 6 So negative two X time C is negative two XC and negative two 7 X times one is negative. Two X is equal to X. 8 Then I'm going to add and subtract like terms. 9 So eight X minus two X six X minus two, 10 XC is equal to ax. 11 And then I'm going to subtract X from both sides and add two X, 12 C to both sides. So six X minus X is five X and that's 13 set equal to two X, 14 C. Then I can divide both sides by two X and I get five 15 X over two X or five over two is equal to 16 C. And so I know that the correct answer must be answer choice.