Math- CAN SOMEONE PLEASE CHECK MY WORK?

posted by .

7x+5y=-26
x=28-6y

solve using substitution

okay so then 196-42y+5y=-26
then combined like terms so
196+37y=-26
37y=-222
y=-6 is this part correct?

• Math- CAN SOMEONE PLEASE CHECK MY WORK? -

You are correct KiKi. y= -6

• Math- CAN SOMEONE PLEASE CHECK MY WORK? -

I believe that is a +6 and most would prefer that you put in another step.
like so:
7(28 - 6y) + 5y = -26, then
196 -42y + 5y = -26
-37y = -222
y=+6

• Math- CAN SOMEONE PLEASE CHECK MY WORK? -

You are correct. The answer is -6.
7(28-6y)+5y=-26
196-42y+5y=-26
37y=-222
37y/37=-222/37
y=-6

• Math- CAN SOMEONE PLEASE CHECK MY WORK? -

The answer is not -6, it is +6.
Both Louise and Michael subtracted incorrectly.
7(28-6y) + 5y = -26
196-42y + 5y = -26
(-42y + 5y is -37y; therefore)
196 - 37y = -26-196 = -222
-37y= -222 and
y=(-222/-37) = +6.

Solve for x now.
x = 28-6y
x = 28-6(+6)
x = 28-36
x - -8.

Now substitute x = -8 and y = +6 into the first equation.
7x + 5y = -26
7(-8) + 5(+6) = -26
-56 + 30 = -26
-26 = -26
Substitute -6 and it won't work.

• Math- CAN SOMEONE PLEASE CHECK MY WORK? -

0y-5-5y=6y-6-26