[Video] Q3: X = y -3 x/2+2y = 6 which ordered pair (x, y) satisfies the system of equations shown above?

Explanation for Question 3 From the Math (No Calc) Section on the Official Sat Practice Test 7

Question three asks, which ordered pair of satisfies the system of equations 2 shown above. So we know here that X 3 is equal to Y minus three. 4 That means that we can substitute in Y minus three into X in this 5 bottom equation. So we're going to start by doing that. 6 So, Y minus three, over two plus 7 two, Y is equal to six. 8 So first thing we can do is multiply both sides of the equation by 9 two, to get Y plus negative three plus 10 four, Y is equal to 12. 11 Then we can add and subtract the wise on the left side of the 12 equation to get five Y minus three is equal to 12. 13 We can add three to both sides, five Ys equal to 15. 14 And finally we can divide both sides by five to get Y is equal 15 to three. Well, 16 since we know that Y is equal to three, we don't actually have to 17 solve for X. And the reason for that is because if you notice all 18 four, answer choices have a different value for Y and only one of them 19 has three as the Y value, which means that we know even without calculating 20 the X value, that B is the correct.