Question

Solve this system of equations using the addition method. 4a - 5b = 7 4a + 5b = 17

Answer 1

\(\large \begin{array}{cccllll}
4a {\color{red}{ - 5b}} = 7 \\
4a {\color{red}{ + 5b}} = 17
\\\hline\\
\square ?+\square ?=\square ?
\end{array}\)

Answer 2

i dont know

Answer 3

If you add the LHS to the LHS, the 5b terms will subtract out.

Answer 4

and so what does that mean

Answer 5

8a = 24
a = 3

Answer 6

k

Answer 7

you'd add them vertically, as robtobey suggested
so see what you'd get