7x + 8y = 25 9x + 10y =35 elimination method please

1 answer:

3 0

$7x +8y = 25 ~~~....(i)\\\\9x +10y = 35~~~ ....(ii)\\\\\text{Multiply equation (ii) by}~ \dfrac 79 ~ \text{and do (ii) - (i):}\\\\\dfrac 79 (9x +10y) - (7x +8y) = \dfrac 79 (35) - 25\\\\\\\implies 7x +\dfrac{70y}9 - 7x -8y = \dfrac{245}9 -25\\\\\\\implies - \dfrac{2y}9 = \dfrac{20}9\\\\\\\implies -2y =20\\\\\implies y =-10\\\\\text{Substitute}~ y = -10~ \text{in equation (i):}\\\\\\7x +8(-10) = 25\\\\\implies 7x = 25 +80\\\\\implies 7x = 105 \\\\\implies x =15\\\\$

$\\\text{Hence}~ (x,y) = (15,-10)$

You might be interested in

Sarah is making a cake using a recipe that requires

Alex73 [517]

Answer:

4/1

because 3+1 is 4 then put 1 so

3 0

3 years ago

Can someone help me find the area

goldfiish [28.3K]

To find the volume of a container, you simply multiply: L(ength) x B(ase) x H(eight).

In total, you should get a volume of 1078in^3 (the bigger container) plus 175in^3 (the smaller container on top of the bigger one). The answer is 1,253in^3.

Hope this helped! :)

7 0

3 years ago

Please help with this question.

ziro4ka [17]

Answer:suchi i think is on the cite

Step-by-step explanation: suchi you need rice at first

4 0

3 years ago

Prove that XR is equivalent to YP by using the terms in geometry, its just proofs

Sophie [7]

PQRS is a parallelogram Given
SR=PQ property of parallelogram
m∠S=m∠Q property of parallelogram
SP=QR property of parallelogram
XP=RY given
SP-XP=QR-RY substitution
SX=QY segment subtraction
ΔSRX is conggruent to ΔQPY SAS theorem (side-angle-side)
XR=YP CPCTC (corresponding parts of congruent triangles are congruent)

3 0

3 years ago

Weights of the vegetables in a field are normally distributed. From a sample Carl Cornfield determines the mean weight of a box

pantera1 [17]

To find the z-score for a weight of 196 oz., use

$z=\frac{x-\mu}{\sigma}=\frac{196-180}{8}=\frac{16}{8}=2$

A table for the cumulative distribution function for the normal distribution (see picture) gives the area 0.9772 BELOW the z-score z = 2. Carl is wondering about the percentage of boxes with weights ABOVE z = 2. The total area under the normal curve is 1, so subtract .9772 from 1.0000.

1.0000 - .9772 = 0.0228, so about 2.3% of the boxes will weigh more than 196 oz.

7 0

3 years ago

7x + 8y = 25 9x + 10y =35 elimination method please​

7x + 8y = 25 9x + 10y =35 elimination method please