Question

Solve using the substitution method. Show your work. If the system has no solution or an infinite number of solutions, state this.
15x + 9y = 240
6x + 3y = 90

Answer 1

15x + 9y = 240
6x + 3y = 90

Rearrange the equation - make one of the variables the subject. Seems easy to make y the subject in the second equation.

6x + 3y = 90
3y = 90 - 6x
y = 30 - 2x

SUBSTITUTE THIS VARIABLE back into the first example.

15x + 9y = 240
15x + 9(30-2x) = 240
15x + 270 - 18x = 240
-3x + 270 = 240
-3x = -30
x = 10

Substitute this answer back into any equation to solve for y.

y = 30 - 2x
y = 30- 2x10
y = 30-20
y = 10

x = 10
y = 10
(10,10)

I think this was obvious from the word go, but there is your solution with working :)
Hope I helped.

Answer 2

Solve using the substitution method. Show your work. If the system has no solution or an infinite number of solutions, state this.

-7x+7y=-7 and
x+9y=61
can someone please help me with this one

Answer 3

is anyone there to help me

Answer 4

can someone please help me with solving using the elimination method for -3x+4y=1 and -6x+6y=-3. If the systime has no solution or an infinite number of solutions, state this.

Answer 5

can someone help me