M
(2y+19)
(5x+20)
n
(4x-11)

(5x+20)+(4x-11)=180(linear pair)

9x+9=180

9x=180-9

9x=171

x=171/9

x=19

now,

(2y+19)+(5x+20)=180(co-interior angle)

2y+19+5×19+20=180

2y+134=180

2y=180

y=180/2

y=90

-7/8

step-by-step explanation:

instead of subtracting you add the -6/8 and -1/8

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15