86 and 87 utilize the Pythagorean theorem. Where those tangent lines meet the circle forms a right angle. So you have a side length of 6 and a hypotenuse of 22. So the missing side length is 21.16. For 87, its the same thing, but you have the 2 legs but are missing the hypotenuse.
The answer is 9.0 because 8.5 is above 5 and to the nearest tenth it would be 9.0
Simon ran slower than 1 mile every 5 minutes.
Because 33 / 5.5 = 6. So he ran 1 mile every 6 minutes, not 5.
X + 5y = 1 . . . . (1)
8x - 2y = 3 . . . .(2)
Solution 1.
From (1), x = 1 - 5y
substituting for x in (2), we have:
8(1 - 5y) - 2y = 3
8 - 40y - 2y = 3
8 - 42y = 3
42y = 5
y = 5/42
x = 1 - 5(5/42) = 1 - 25/42 = 17/42.
Solution 2.
Multiply (1) by 8, to get:
8x + 40y = 8 . . . . . (3)
(3) - (2) = 40y - (-2y) = 8 - 3
42y = 5
y = 5/42
substitute for y into (3), to get:
8x + 40(5/42) = 8
8x + 100/21 = 8
8x = 8 - 100/21 = 68/21
x = (68/21)/8 = 17/42
