If you have at least as many equations as your have unknown variables, the 'system' is solvable (unless the equations are copies of eachother).
In this case, isolate one letter and plug it in the other. I'm going for the 2a in the bottom one (it doesn't matter)
2a - 4b = 12 => (divide by two and move the b's to the other side)
a = 6 + 2b. (plug this one into the top equation)
4(6+2b) + 6b = 10 => 24+8b+6b = 10 => 24 + 14b = 10 => 14b = -14 => b=-1
a = 6 + -2 = 4.
So a=4 and b=-1.
Answer:b,they are not proportional
Step-by-step explanation:
Answer:
1) James brother is 10-x years old
2) James was 3 years ago x-3 years old
3) James brother was 3 years ago 7-x years old
4) 3(x-3)=7-x
5) James is 4 years old, his brother is 6 years old
Step-by-step explanation:
3) 10 - x - 3 = 7 - x
5) 3* James age 3 years ago = James brothers age 3 years ago
<=> 3*(x-3) = 7-x
<=> 3x - 9 = 7 - x
<=> 4x = 16
<=> x = 4
