Question

3a+5b=4
4a+3b=2
find a and b please

Answer 1

Multiply the top equation by 3 and the bottom by 5:

9a + 15b = 12
20a + 15b = 10

Now subtract one from the other, and the b's vanish:

11a = -2
a = -2/11
Now plug that value into either equation to get b:
3(-2/11) + 5b = 4
-6 + 55b = 44
55b = 50
b = 10/11

Check these values in the other equation:

4(-2/11) + 3(10/11)
= (-8 + 20)/11 = 22/11 = 2
looks ok.