3a + 7 b = 2 2a + 9 b = 15

solve this linear equations using elimination method

please show your working ✨✨ THANK YOU

a = -87/13

b = 41/13

Step-by-step explanation:

3a + 7b = 2

2a + 9b = 15

You need to have one of the coefficients have the same number but the opposite sign in both equations.  Multiply the first equation by -2 and the second equation by 3.  You will then be able to cancel out a and solve for b.

-2(3a + 7b) = -2(2)

-6a - 14b = -4

3(2a + 9b) = 3(15)

6a + 27b = 45

-6a - 14b = -4

6a + 27b = 45

0a + 13b = 41

13b = 41

b = 41/13

Plug in the b-value into one of the given equations and solve for a.

3a + 7b = 2

3a + 7(41/13) = 2

3a + 287/13 = 2

3a = -261/13

a = -87/13

the equation cos(35) =a/25 can be used to find the length of bc what is the length of bc? round to the nearest tenth

step-by-step explanation: