Question

A number is 9 more than another number. Twice the sum of the two numbers is 10. Find the two numbers.

Answer 1

Answer:

7, -2

Step-by-step explanation:

we call the first number "X" and the second one "Y"

X is 9 more than Y! which means we need to add 9 to Y so it'll be equal to X. so: Y+9=X

also 2×(X+Y)=10

you can also write this down as: 2X+2Y=10

now we have:

X=Y+9

2X+2Y=10

you can now put what equals to X in the second Equation:

2(Y+9)+2Y=10 => 2Y+18+2Y=10 => 4Y=10-18 =>Y= -2

the only thing left to do is to put Y= -2 in the first equation:

X= -2+9 => X=7

Answer 2

• Answer:

a = 7

b = - 2

• Step-by-step explanation:

a = b + 9

2(a + b) = 10 => a + b = 5

replace a

(b + 9) + b = 5

2b = 5 - 9

2b = - 4

b = - 2

replace b

a = - 2 + 9

a = 7