Question

4a-3b=10 2a+b=10 solve by using elimination method

Answer 1

Answer:

a = 4 , b = 2

Step-by-step explanation:

4a - 3b = 10 → (1)

2a + b = 10 → (2)

Multiplying (2) by 3 and adding to (1) will eliminate the b- term

6a + 3b = 30 → (3)

Add (1) and (3) term by term to eliminate b

10a + 0 = 40

10a = 40 ( divide both sides by 10 )

a = 4

Substitute a = 4 into either of the 2 equations and solve for b

Substituting into (2)

2(4) + b = 10

8 + b = 10 ( subtract 8 from both sides )

b = 2

Answer 2

4a-3b=10 (first equation)

2a+b =10 (second equation)

Now you multiply by -2 to get rid of a (as it is also common factor) but remember to always multiple the whole equation too
So…

4a-3b=10

-4a-2b =-20 (change of sign because positive x negative= negative but I’m sure you know that already)

Now your equation will equal b=-10 (4a-4a=0 and 3b-2b= b and 10-20=-10)

To find a you’ll have to sub b=-10 in any original equation but I will sub it in the second equation originally

2(-10)+b=10
-20+b=10
B=30 (-20+30=10)