Equations ax + by = e, CX + dy = f

x=(de-bf)/(ad-bc) y=(af-ce)/(ad-be)
acx+bcy=ce acx+ady=af
Subtract the two formulas to get y, and then substitute them to get X

If the solution of the system of equations ax + by = m CX + dy = n about X, y is x = 3, y = 4, then the solution of the system of equations 3ax + 5by = m 3CX + 5dy = n about X, y is

aX +bY = m
CX + dy = n, so from the title we can know: x = 3, y = 4. Because: x = 3x, y = 5Y; so x = 1, y = 4 / 5

To solve the equations ax + by = 1, CX + dy = 1, a misread C and get x = - 19 / 6, y = - 3 / 2, B misread D and get x = - 6, y = - 19 / 7, and find the value of a and B

Substitute x = - 19 / 6, y = - 3 / 2; X = - 6, y = - 19 / 7 into ax + by = 1 to get
（-19/6）a+（-3/2）b=1
-6a+（-19/7）b=1
The solution is a = 3, B = - 7
Analysis, because a and B only read the wrong number in CX + dy = 1, so the two solutions can make ax + by = 1 hold, then substituting the two solutions, we will get the values of a and B

(n-2) * 180 ∶ 360 = 13 ∶ 12

This problem is easy to calculate, as long as (n-2) * 180 = 390, so n = 6 / 25

The solution of x square plus two and x minus three equals zero

X = 1 or - 3
.

Two minus three is five plus three

2-x/3=x/5+3
x/3+x/5=2-3
8x/15=-1
x=-15/8

What is 540 minus 360

180

Equations ax + by = e, CX + dy = f