i need help on my homework.

i need help on 2 questions.

1) A ship leaves port and sails 74km north. It then turns and sails 68km east. Find the distance and the bearing of the shop from the port.

The second question is..

2) Solve this equation 4x(cubed)-7=23

please help!! would be very grateful! i think i know what to do.. but what i do doesn't seem to be working! i hope someone that is online could help me, please!..

Answers
To answer your first question you would need to draw the diagram out and you will see that it forms a right angled triangle. With this sort of triangle you then need to use pythagoras to find out the longest side (the two shorter sides are 74 and 68). So 74 squared + 68 squared = longest side squared 10100 = longest side squared to get the longest side we just need to square root 10100 = 100.5 km. To work out the bearing we want the angle formed by the 68km side and the 100.5 km side. To work out the angle we can use trigonomtery. Again it is easier when you have drawn and labelled the triangle but i am just going to have to explain without and hope you understand! cos angle = 68/100.5 angle = cos -1 (68/100.5) = 47.4 degrees For your second question you need to first get x by itself on the left hand side so the first step would be to take the -7 to the right hand side where it would become + 7 (inverse rule) to get 4x cubed = 30 then we need to divide by 4 x cubed = 7.5 now we need to do the cube root of 7.5 using your calculator so x is now 1.96 Hope you understood all of that!
javaid.aslam
21 February 2011
thank you again! i did understand that, thank you very much! im very grateful!!
rachel_dance123
21 February 2011
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