Step-by-step explanation:
Given
2a + b = 6......equation 1
a - 6 = b
a = b + 6........equation 2
Putting equation 2 in equation 1
2 ( b + 6 ) + b = 6
2b + 12 + b = 6
3b = 6 - 12
3b = - 6
b = - 6 / 3
Therefore b = - 2
Now
a = - 2 + 6 = 4
hope it will help :)
i dont have much time to go through all the work but i can tell you that since its a 90 degree angle, your equation would be 90=15x-2+7x+4. Once you get the value of X plug that into each of the equations. For example if your x value was 2 you would do 15(2)-2. Thats just an example.
Terrance is training at 12 miles per hour and Jesse is training at 8 miles per hour