50 will mark show all use the linear combination method to solve the system of equations. explain each step of your solution. if steps are not explained, you will not receive credit for that step. 2x+9y= -26 -3x-7y=13

x=5, y=-4

Step-by-step explanation:

2x+9y = -26

-3x-7y = 13

Multiply the first equation by 3

3(2x+9y = -26)

6x +27y = -78

Multiply the second equation by 2

2(-3x-7y = 13)

-6x -14y = 26

Add these two equations together

6x +27y = -78

-6x -14y = 26

13y = -52

Divide by 13

13y/13 = -52/13

y = -4

Now we need to find x

2x+9y = -26

2x+9(-4) = -26

2x-36=-26

Add 36 to each side

2x-36+36 = -26+36

2x=10

Divide by 2

2x/2 =10/2

x=5

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.