Question

What is the solution to the given system of equations?

7a-12b = 10
-2a-4b = 12


pls help me i don’t understand

Answer 1

a=−2 and b=−2

Explanation:

Let's solve your system by substitution.

7a−12b=10;−2a−4b=12

Step: Solve7a−12b=10for a:

7a−12b=10

7a−12b+12b=10+12b(Add 12b to both sides)

7a=12b+10

7a/7=12b+10/7

(Divide both sides by 7)

`\sf \: a = (12)/(7) b + (10)/(7)`

Step: Substitute: 12/7b+10/7 for a in−2a−4b=12:

−2a−4b=12

−2(12/7b+10/7)−4b=12

−52/7b + −20/7=12(Simplify both sides of the equation)

−52/7b+−20/7+20/7=12+20/7

(Add 20/7 to both sides)

−52/7b=104/7

`\sf \: ( ( - 52)/(7)b )/( ( - 52)/(7) ) = ( (104)/(7) )/( ( - 52)/(7) )`

(Divide both sides by (-52)/7)

b=−2

Step: Substitute −2 for b in a =12/7b+10/7:

a=/12/7b+10/7

a=12/7(−2)+10/7

a=−2(Simplify both sides of the equation)