Explanation for Question 20 From the Math (No Calc) Section on the Official Sat Practice Test 1
So number 20 tells us the A's equal to five, 2 route two, and they also tell us that two way is equal to root 3 of two X, and we need to find the value of X. 4 So the first thing that we can think about doing is finding out what 5 two H is using this equation. 6 So if a is five times root two, 7 then two a would be two times that right, 8 two times five root two, which is also equal to 10 root two, 9 cause I can multiply the two in the five together. 10 So now I know that two a is equal to two things is equal 11 to 10 root to and is equal to two X. 12 So since both of those are equal to two eight, they're also equal to 13 each other. And I can write a new equation that shows that 10 route 14 two is equal to route two X, 15 which works because they're both equal to egg. 16 And so now, since both of them have a radical, 17 the way I get rid of that radical is by squaring both sides. 18 Now, if I square the side, I need to remember to square the 10 19 and the route to that will give me 100 times two. 20 And then on this side I can square the root of two X. 21 These will cancel out and I'll just get two X now, 22 100 times two that's 200. So we know 200 is equal to two X 23 and the software X, I just need to divide by two. 24 So I get that 100 is equal to X.